DE102022118851A1 - PHOTOCHROMIC POLYMER COMPOSITION - Google Patents

Abstract

The present invention relates to a photochromic polymer composition composed of a polymer polycarbonate (PC) and poly(methyl methacrylate) (PMMA) and a photochromic compound selected from a spiropyran and a diarylethene, and articles containing this composition. The present invention further relates to methods for producing the photochromic polymer composition and for producing articles containing the photochromic polymer composition.

Description

Introduction

In the automotive sector, the first plastic parts were introduced in the 1970s to reduce the weight and price of cars. Since then, the proportion of plastics in vehicles has increased steadily and is now 20% of a vehicle's total mass. To meet the high production rates of the automotive industry, plastic injection molding is often used to shape parts. This process allows identical items to be manufactured at high speed from different materials to achieve very different geometries and surfaces. A large part of door panels, dashboards and center consoles consist of injected thermoplastic parts. In order to create ever more innovative constructions, colors, textures and contrasts can be varied. This requires increasingly complex and technical tools, although the injection molding machines and their molds are already very expensive and require a complex and expensive design.

Often an item is desired that consists of two parts: a transparent part that allows light to pass through and an opaque part that does not allow light to pass through. Currently, this type of item is manufactured using the two-component injection molding process (one transparent and one opaque material). This requires special and expensive presses and molds. In addition, the geometry of the parts is limited by the design of the molds and the spatial resolution between the opaque and transparent parts does not reach the very tight tolerances sometimes required. To achieve good resolution, the interface must be controlled from a molecular perspective, which is why chemical rather than mechanical systems are used.

To overcome these disadvantages, the development of a new material could replace the complex, expensive and geometrically limited process. In particular, the incorporation of a chemical species called photochromic compounds into the transparent material would make it possible to obtain an intelligent material programmed to become cloudier depending on the incidence of light. These compounds have the ability to change color when exposed to light. The modified material could be injection molded in a single step, and the resulting 3D article could be selectively transparent, colored, or even opaque on the surface and throughout the area by exposure to light. This process would therefore have the advantage of reducing design and tooling costs and providing access to new, more complex geometries of the developing material.

A solvent-based technique is generally used to introduce the photochromic compounds into the thermoplastic matrix. In this widely used process, the photochromic compounds are dissolved with the thermoplastic in a solvent, which is then evaporated. However, this technique involves volatile organic compounds (VOCs), which are undesirable in the industrial environment, and strong parts cannot be obtained. However, compounding and injection molding without solvents requires high temperatures that can degrade the photochromic compounds.

Li et al. (New J Chem, 2018, 42, 10885-10890) discloses the melt compounding of inorganic WO ₃ nanosheets or WO ₃ nanorods in a polymer matrix of poly(methyl methacrylate-co-butyl acrylate) P(MMA-cp-BA). The material showed coloration upon UV irradiation, and upon completion of UV irradiation, it decolorized and returned to its original state.

Micciche et al. (J Polym Sci B Polym Phys, 2016, 54, 1593-1601) discloses the preparation of a photochromic formulation by compounding and extruding a dry blended mixture of polycarbonate and a spironaphtoxazine or a spironaphthopyran. However, these classes of compounds exhibit rapid discoloration, whereas in the present application slow or no discoloration is desired.

Optov et al., Polym Sci Ser B, 2018, refer to a two-step process in which 1 wt% spiropyran powder is thoroughly mixed with polypropylene granules to allow diffusion into the surface of the granules instead of homogeneous mixing , followed by pressing at 260 °C into layers of 100 µm. The thin layers colored quickly when illuminated and also faded quickly in the dark. Without being bound by theory, such thin films can influence the molecular organization of the photochromic compound in the polymer matrix and the core-shell effect during aging.

It is therefore an object of the present invention to provide compositions comprising a polymer and a photochromic compound which can be used to produce an article with a transparent and homogeneous appearance, having a high contrast between the exposed and unexposed parts, which is a has spatial resolution in the micrometer range for color change, which has a permanent (irreversible) or non-permanent (reversible) color depending on the application and has low production costs and has a thickness of at least 1 mm.

A further object of the present invention is to provide a simple and reliable method of manufacturing an article comprising a polymer and a photochromic compound which can be carried out in the absence of solvents with no or negligible degradation of the photochromic compound.

Another object of the present invention is to provide articles that are sufficiently strong and stable to be used as automobile parts.

Summary of the invention

1. (a) 90,00 bis 99,99 Gew.-% eines Polymers, ausgewählt aus der Gruppe bestehend aus Polycarbonat (PC) und Poly(methylmethacrylat) (PMMA) und Gemischen davon; und
2. (b) 0,01 bis 10,00 Gew.-% mindestens einer photochromen Verbindung, ausgewählt aus der Gruppe bestehend aus:
   • (i) einem Spiropyran der Formel (I)
     
     wobei R₁ ausgewählt ist aus C_1-6-Alkyl, C_2-6-Alkenyl, C_1-6-Hydroxyalkyl; R₂ und R₃ unabhängig ausgewählt sind aus C_1-6-Alkyl und C_2-6-Alkenyl, oder wobei R₂ und R₃ zusammen C₃-C₇-Cycloalkyl bilden; R₄, R₅ und R₆ unabhängig ausgewählt sind aus H, -NO₂, C_1-6-Alkyl, C_2-6-Alkenyl und C_1-6-Alkoxy, wobei mindestens eines von R₄, R₅ und R₆ -NO₂ ist. und/oder
   • (ii) einem Diarylethen der Formel (IIa), (IIb) oder (IIc)
     
     
     
     wobei R₇ und R_7' beide -CN sind, oder R₇ and R_7' zusammen einen perfluorierten Cyclopentenring bilden; R₈ und R_8' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl und C_2-6-Alkenyl; R₉ und R_9' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl, C_2-6-Alkenyl, Phenyl und Benzyl; R₁₀ und R_10' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl, C_2-6-Alkenyl, Phenyl und Benzyl; R₁₁ und R_11' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl, C_2-6-Alkenyl, Phenyl und Benzyl; oder wobei in Formel (IIa) R₉/R_9' and R₁₀/R_10' zusammen einen Benzolring bilden;
   wobei sich die Mengenangaben auf das Gesamtgewicht der photochromen Polymerzusammensetzung beziehen.

The present invention relates to a photochromic polymer composition comprising:

1. (a) 90.00 to 99.99% by weight of a polymer selected from the group consisting of polycarbonate (PC) and poly(methyl methacrylate) (PMMA) and mixtures thereof; and
2. (b) 0.01 to 10.00% by weight of at least one photochromic compound selected from the group consisting of:
   • (i) a spiropyran of the formula (I)
     
     where R ₁ is selected from C _1-6 alkyl, C _2-6 alkenyl, C _1-6 hydroxyalkyl; R ₂ and R ₃ are independently selected from C _1-6 alkyl and C _2-6 alkenyl, or wherein R ₂ and R ₃ together form C ₃ -C ₇ cycloalkyl; R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , C _1-6 alkyl, C _2-6 alkenyl and C _1-6 alkoxy, where at least one of R ₄ , R ₅ and R ₆ -NO ₂ is. and or
   • (ii) a diarylethene of the formula (IIa), (IIb) or (IIc)
     
     
     
     where R ₇ and R _7' are both -CN, or R ₇ and R _7' together form a perfluorinated cyclopentene ring; R ₈ and R _8' are identical and are selected from H, C _1-6 alkyl and C _2-6 alkenyl; R ₉ and R _9' are identical and are selected from H, C _1-6 alkyl, C _2-6 alkenyl, phenyl and benzyl; R ₁₀ and R _10' are identical and are selected from H, C _1-6 alkyl, C _2-6 alkenyl, phenyl and benzyl; R ₁₁ and R _11' are identical and are selected from H, C _1-6 alkyl, C _2-6 alkenyl, phenyl and benzyl; or where in formula (IIa) R ₉ /R _9' and R ₁₀ /R _10' together form a benzene ring;
   where the quantities refer to the total weight of the photochromic polymer composition.

R ₁ is preferably selected from methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, ethenyl, propen-1-yl, buten-1- yl, penten-1-yl, hexen-1-yl, hydroxymethyl, 1-hydroxyethyl, 1-hydroxypropyl, 2-hydroxypropyl, 1-hydroxybutyl, 1-hydroxypentyl, 1-hydroxyhexyl. More preferably, R ₁ is selected from methyl and 1-hydroxyethyl.

Preferably R ₂ and R ₃ are independently selected from methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, ethenyl, propen-1-yl, buten-1-yl, penten-1-yl , hexen-1-yl, or where R ₂ and R ₃ together form cyclopentyl, cyclohexyl or cycloheptyl. More preferably, R ₂ and R ₃ are both methyl or R ₂ and R ₃ together form cyclohexyl.

R ₄ , R ₅ and R ₆ are preferably independently selected from H, -NO ₂ , methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl , ethenyl, propen-1-yl, buten-1-yl, penten-1-yl, hexen-1-yl, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, sec-butoxy, tert-butoxy , n-pentoxy, n-hexoxy.

R ₄ , R ₅ and R ₆ are preferably independently selected from H, -NO ₂ , methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, n-hexoxy .

Preferably R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , methyl, sec-butyl and methoxy. Preferred is one of R ₄ , R ₅ and R ₆ -NO ₂ .

R ₈ and R _8' are preferably identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, ethenyl, propene -1-yl, buten-1-yl, penten-1-yl and hexen-1-yl. More preferably R ₈ and R _8' are identical and are selected from methyl and ethyl, even more preferably R ₈ and R _8' are identical and are methyl.

R ₉ and R _9' are preferably identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, ethenyl, propene -1-yl, buten-1-yl, penten-1-yl, hexen-1-yl, phenyl and benzyl. More preferably, R ₉ and R ₉ are identical and are selected from methyl and phenyl.

R ₁₀ and R _10' are preferably identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, ethenyl, Propen-1-yl, Buten-1-yl, Penten-1-yl, Hexen-1-yl, Phenyl and Benzyl. More preferably, R ₁₀ and R _10' are identical and are selected from H or methyl;

R ₁₁ and R _11' are preferably identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, ethenyl, propene -1-yl, buten-1-yl, penten-1-yl, hexen-1-yl, phenyl and benzyl. More preferably, R ₁₁ and R _11' are identical and are selected from H or methyl;

Most preferably, the spiropyran is selected from the group consisting of:

Most preferably, the diarylethene is selected from the group consisting of:

Preferably the photochromic compound is in an amount of 0.01 to 5.00% by weight, more preferably in an amount of 0.01 to 2.00% by weight, even more preferably in an amount of 0.01 to 0.90% by weight, more preferably in an amount of 0.01 to 0.60% by weight, most preferably in an amount of 0.03 to 0.60% by weight, based on the total weight the photochromic polymer composition.

It is preferred that the at least one photochromic compound contained in the photochromic polymer composition is selected from spiropyrans of formula (I). Alternatively, it is preferred that the at least one photochromic compound contained in the photochromic polymer composition is selected from diarylethenes of the formula (IIa), (IIb) or (IIc).

Preferably the spiropyran is in an amount of 0.01 to 5.00% by weight, more preferably in an amount of 0.01 to 2.00% by weight, even more preferably in an amount of 0.01 to 0 .90% by weight, more preferably in an amount of 0.01 to 0.60% by weight, most preferably in an amount of 0.10 to 0.60% by weight, based on the total weight of the photochromic polymer composition.

Preferably the diarylethene is in an amount of 0.01 to 10.00% by weight, more preferably from 0.01 to 5.00% by weight, more preferably from 0.01 to 2.00% by weight, even more preferably from 0.01 to 0.90 wt%, even more preferably from 0.03 to 0.60 wt%, even more preferably from 0.08 to 0.60 wt%, most preferably from 0.10 to 0.60% by weight, based on the total weight of the photochromic polymer composition.

It is preferred that the composition be free of volatile organic compounds (VOC). Preferably the composition comprises 0.05 or less, more preferably 0.01% by weight or less of VOC based on the total amount of the composition.

The present invention further relates to an article, preferably an injection molded article, comprising the composition of the present invention. The article is preferably in the form of a film, a plate or a panel.

It is further preferred that the article has a light transmittance of 7% or less, determined according to DIN EN ISO 13468-1, 2 under illumination or determined according to DIN EN ISO 8980-1.

The present invention further relates to a process for producing the photochromic composition, the process comprising compounding PC or PMMA and a photochromic compound to form the thermoplastic composition. The compounding is preferably carried out at a temperature in the range from 180 to 230 ° C.

The present invention further relates to the manufacture of an article comprising the composition of the present invention, the method comprising compounding PC or PMMA and a photochromic compound to form the thermoplastic composition, followed by injecting and molding the thermoplastic composition into the Article.

Preferably, the compounding in the process for producing the article is carried out at a temperature in the range of 180 to 230 ° C. The injection to produce the article is preferably carried out at a temperature gradient in the range of 220 to 350 ° C. Preferably, the molding to produce the article is carried out at a temperature in the range of 80 to 120°C.

Preferably, the processes of the present invention are carried out in the absence of volatile organic components (VOC).

Unless otherwise stated, the amounts of the individual compounds are given in percent by weight (wt.%, wt./wt.) based on the total amount of the photochromic polymer composition of the present invention.

Detailed description of the invention

The present invention relates to a composition comprising a polymer and a photochromic compound, an article containing this composition and methods for producing the composition or article.

Photochromic polymer composition

1. (a) 90,00 bis 99,99 Gew.-% eines Polymers, ausgewählt aus der Gruppe bestehend aus Polycarbonat (PC) und Poly(methylmethacrylat) (PMMA) und Gemischen davon; und
2. (b) 0,01 bis 10,00 Gew.-% mindestens einer photochromen Verbindung, ausgewählt aus der Gruppe bestehend aus:
   • (i) einem Spiropyran der Formel (I)
     
     wobei R₁ ausgewählt ist aus C_1-6-Alkyl, C_2-6-Alkenyl, C_1-6-Hydroxyalkyl; R₂ und R₃ unabhängig ausgewählt sind aus C_1-6-Alkyl und C_2-6-Alkenyl, oder wobei R₂ und R₃ zusammen C₃-C₇-Cycloalkyl bilden; R₄, R₅ und R₆ unabhängig ausgewählt sind aus H, -NO₂, C_1-6-Alkyl, C_2-6-Alkenyl und C_1-6-Alkoxy, wobei mindestens eines von R₄, R₅ und R₆ -NO₂ ist. und/oder
   • (ii) einem Diarylethen der Formel (IIa), (IIb) oder (IIc)
     
     
     
     wobei R₇ und R_7' beide -CN sind, oder R₇ and R_7' zusammen einen perfluorierten Cyclopentenring bilden; R₈ und R_8' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl und C_2-6-Alkenyl; R₉ und R_9' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl, Phenyl und Benzyl; R₁₀ und R_10' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl, Phenyl und Benzyl; R₁₁ und R_11' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl, Phenyl und Benzyl; oder wobei in Formel (IIa) R₉/R_9' and R₁₀/R_10' zusammen einen Benzolring bilden;
   wobei sich die Mengenangaben auf das Gesamtgewicht der photochromen Polymerzusammensetzung beziehen.

Accordingly, the present invention relates to a photochromic polymer composition comprising:

1. (a) 90.00 to 99.99% by weight of a polymer selected from the group consisting of polycarbonate (PC) and poly(methyl methacrylate) (PMMA) and mixtures thereof; and
2. (b) 0.01 to 10.00% by weight of at least one photochromic compound selected from the group consisting of:
   • (i) a spiropyran of the formula (I)
     
     where R ₁ is selected from C _1-6 alkyl, C _2-6 alkenyl, C _1-6 hydroxyalkyl; R ₂ and R ₃ are independently selected from C _1-6 alkyl and C _2-6 alkenyl, or wherein R ₂ and R ₃ together form C ₃ -C ₇ cycloalkyl; R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , C _1-6 alkyl, C _2-6 alkenyl and C _1-6 alkoxy, where at least one of R ₄ , R ₅ and R ₆ -NO ₂ is. and or
   • (ii) a diarylethene of the formula (IIa), (IIb) or (IIc)
     
     
     
     where R ₇ and R _7' are both -CN, or R ₇ and R _7' together form a perfluorinated cyclopentene ring; R ₈ and R _8' are identical and are selected from H, C _1-6 alkyl and C _2-6 alkenyl; R ₉ and R _9' are identical and are selected from H, C _1-6 alkyl, phenyl and benzyl; R ₁₀ and R _10' are identical and are selected from H, C _1-6 alkyl, phenyl and benzyl; R ₁₁ and R _11' are identical and are selected from H, C _1-6 alkyl, phenyl and benzyl; or where in formula (IIa) R ₉ /R _9' and R ₁₀ /R _10' together form a benzene ring;
   where the quantities refer to the total weight of the photochromic polymer composition.

Polymers

In the present invention, poly(methyl methacrylates) (PMMA) and polycarbonates (PC) are considered as polymeric materials. These classes of polymers exhibit thermoplastic properties and are often used in the automotive industry due to their mechanical and optical properties suitable for this area.

Thermoplastics are a class of polymers that soften as temperature increases without decomposing and solidify again when cooled. The transition between the glassy (solid) and rubbery states occurs at the glass transition temperature (Tg), the temperature at which the polymer chains have enough energy to gain mobility. Little by little, the chain segments begin to rotate, which leads to a softening of the material.

When the temperature is increased and the material has become soft and malleable, it can be formed into the desired shape to obtain pellets, wires, plates or more complex objects. In contrast to thermoset materials, the material can generally be reshaped over several cycles and therefore recycled. Due to this property, extrusion and injection molding processes are particularly suitable for thermoplastics. These processes enable the cost-effective production of parts in large series and are therefore widely used in industry, particularly in the automotive sector.

PMMA and PC are also optical quality transparent materials suitable for vehicle interiors. These thermoplastics meet the optical and mechanical properties required in the automotive sector and have excellent stability. They are transparent to visible light and respond appropriately to impact.

Numerous PMMA and PC polymer variants are known and commercially available. Those skilled in the art will know how to select an appropriate PMMA and PC polymer for use in the present invention. The polymers PMMA and PC preferably have a light transmittance of 90% or more in the VIS range, determined according to DIN EN ISO 13468-1.2, and a Tg of at least 110 ° C.

Preferably the photochromic polymer composition comprises PMMA. Preferably the photochromic polymer composition comprises PC. Preferably, the photochromic polymer composition comprises a mixture of PMMA and PC, wherein the weight ratio of PMMA to PC in the photochromic polymer composition is preferably in the range of 90:10 to 10:90.

It is further preferred that the polymer is in an amount of 95.00 to 99.99% by weight of the polymer, more preferably in an amount of 98.00 to 99.99% by weight, even more preferably in an amount from 99.00 to 99.98% by weight, most preferably in an amount of 99.40 to 99.90% by weight, based on the total weight of the photochromic polymer composition.

Photochromatic compounds

The photochromic composition according to the invention includes photochromic compounds. Chromium compounds are compounds that form under the influence of an external stimulus, such as: B. temperature, current, solvation or light can change their color. The phenomenon of photochromism was first observed in 1867 by J. Fritzsch, who noted that a tetracene solution changes color from orange to colorless in daylight and back to orange in darkness (J. Fritzsch J, Comptes redus de l'Academie des Science, Sci. Paris, 1867, 69, 78).

The International Union of Pure and Applied Chemistry (IUPAC) currently defines photochromism as follows: "[a] Reversible transformation of a molecular entity between two forms, A and B, having different absorption spectra, induced in one or both directions by absorption of electromagnetic radiation. The spectral change produced is typically, but not necessarily, of visible color and is accompanied by differences in other physical properties. The thermodynamically stable form A is transformed by irradiation into form B. The back reaction can occur thermally (photochromism of type T) or photochemically (photochromism of type P)" and can be represented by the following equilibrium: $$\text{A}\underset{{\text{hv}}_2\text{ou}\Delta }{\overset{{\text{hv}}_1}{\rightleftarrows }}\text{b}$$

A photochromic compound is a chemical species that can change reversibly from form A to form B when exposed to light, which differs in its absorption spectrum. Chemical species A changes its electron configuration by interacting with an electromagnetic wave. When molecule A has converted to form B, it is said to be photoactivated.

The reverse reaction B→A can then either occur spontaneously through a thermal mechanism that can be accelerated by light, or the B form is thermally stable and the reverse reaction occurs photochemically. In the first case (ΔE ≈ kT) the connection is of type T and in the second case it is of P-type (ΔE >> kT). In addition, photochromic species are distinguished according to the wavelengths of the absorption maximum λmax of their two forms: when λAmax < λBmax, the photochromism is said to be positive (transition from the colorless to the colored form) and when λAmax > λBmax, it is said to be negative or inverse (transition from the colored to the colorless form).

The first photochromic chemicals to be studied and used for industrial applications were inorganic photochromic compounds. The most common species in the literature are organometallic complexes ( Nakai H & Isobe K, Coord Chem Rev, 2010, 254, 1652-2662 ) and transition metal oxides (oxides of tungsten, molybdenum, titanium, vanadium, etc.), which, despite their thermal stability, have a weak color, generally in the blue range, and due to the Transfer of electrons from the oxygen to the metal occurs only slowly, on the order of several days ( Fleisch TH et al, J Chem Phys, 1982, 76, 780-786; Shigesato Y, Jpn J Appl Phys, 1991, 30, 1437-1462 ; Kayan ABA et al., Small 2021, 17(32), 2100621 ). The most developed are silver salts and especially silver halides, which are used in the eyewear industry to produce photochromic lenses in mineral glass.

In addition, a variety of photochromic organic compounds have been discovered and studied. Type T photochromic compounds with positive photochromism include spiropyrans and spirooxazines, spironaphthoxazines, bianthrones, chromenes, naphthopyrans, stilbenes and azobenzenes. P molecules with positive photochromism include fulgides, fulgimides or diarylethenes.

Type T spiropyrans consist of an indole group and a benzopyran group orthogonally linked by a spiral carbon atom. Under the influence of UV radiation, the Cspiro-O bond is broken and a merocyanine is formed that absorbs in the visible range. The reversible transition of two unconjugated electron systems and a conjugated planar form leads to an equilibrium between a colorless and a colored form. Spiropyrans can be synthesized in a few synthetic steps under simple reflux and with yields between 70 and 98% ( Minkin VI, Chem Rev, 2004, 104, 2751-2776 ).

Type T spiropyrans are often used as a coating for eyeglass lenses because they are light sensitive, allowing the lens to be quickly tinted when exposed to sunlight. However, because these molecules are sensitive to their environment, the balance between the colorless and colored forms depends on the environment, depending on pH, polarity or temperature. Spiropyrans have been used in inks, paints, and textiles, as well as in optical data storage systems and as biotracers or chemical detectors ( Tsa WK, ACS Appl Mater Interfaces, 2017, 9, 30918-30924 ; Sharafian MH et al, Langmuir, 2017, 33, 8023-8031 ; Kawata S & Kawata Y, Chem Re, 2000, 100, 1777-1788 ; Byrne R et al., Biosens Bioelectron, 2010, 26, 1392-1398 ; Bahajaj AA et al., Pigment Resin Technol, 2010, 39, 71-76 ).

P-Diarylethenes are thermally irreversible but photochemically reversible photochromic molecules. This property makes them photochromic systems that are reversible when necessary, i.e. only when exposed to light. The photochromism of diarylethenes is the result of a 4n+2 cyclization under light irradiation. The photocyclization occurs under UV irradiation and the photoreversion reaction occurs under irradiation in the visible range. Generally, the open form of the molecule is colorless and the closed form is colored, but it is also possible for both forms to have coloring, although these are different and varied depending on the chemical structure of the molecule. Diarylethenes have been used in applications such as: B. optical storage systems ( Irie M et al, Chem Rev 2014, 114, 12174-12277 ), optical switching devices ( Yoshida T et al., J Photochem Photobiol A: Chem, 1996, 95, 265-270 ), in macroscopic photomechanical bending ( Ohshima S et al., Chem Sci, 2015, 6, 5746-5752 ), but also in the transport and release of target molecules Zhang J et al, Mater Hori, 2014, 1, 169-184 ) and in super-resolution microscopy ( Irie M & Morimoto, Bull Chem Soc Jap, 2018, 91, 237-250 ) used.

wobei
R₁ ausgewählt ist aus C_1-6-Alkyl, C_2-6-Alkenyl, C_1-6-Hydroxyalkyl;
R₂ und R₃ unabhängig ausgewählt sind aus C_1-6-Alkyl und C_2-6-Alkenyl, oder wobei R₂ und R₃ zusammen C₃-C₇-Cycloalkyl bilden;
R₄, R₅ und R₆ unabhängig ausgewählt sind aus H, -NO₂, C_1-6-Alkyl, C_2-6-Alkenyl und C_1-6-Alkoxy,
wobei mindestens eines von R₄, R₅ und R₆ -NO₂ ist.The photochromic polymer composition preferably comprises a spiropyran of the formula (I)

where
R ₁ is selected from C _1-6 alkyl, C _2-6 alkenyl, C _1-6 hydroxyalkyl;
R ₂ and R ₃ are independently selected from C _1-6 alkyl and C _2-6 alkenyl, or wherein R ₂ and R ₃ together form C ₃ -C ₇ cycloalkyl;
R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , C _1-6 alkyl, C _2-6 alkenyl and C _1-6 alkoxy,
where at least one of R ₄ , R ₅ and R ₆ is -NO ₂ .

R ₁ is preferably selected from methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, ethenyl, propen-1-yl, buten-1- yl, penten-1-yl, hexen-1-yl, hydroxymethyl, 1-hydroxyethyl, 1-hydroxypropyl, 2-hydroxypropyl, 1-hydroxybutyl, 1-hydroxypentyl, 1-hydroxyhexyl.

R ₁ is preferably selected from C _1-6 alkyl and C _1-6 hydroxyalkyl. More preferably, R ₁ is selected from methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, hydroxymethyl, 1-hydroxyethyl, 1-hydroxypropyl, 2 -Hydroxypropyl, 1-hydroxybutyl, 1-hydroxypentyl, 1-hydroxyhexyl. More preferably, R ₁ is selected from methyl, hexyl and 1-hydroxyethyl.

R ₂ and R ₃ are preferably selected from C ₁ -C ₆ alkyl. R ₂ and R ₃ together preferably form C ₅ -C ₇ cycloalkyl. Preferably R ₂ and R ₃ are independently selected from methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, or R ₂ and R ₃ together form cyclopentyl, cyclohexyl or cycloheptyl.

More preferably, R ₂ and R ₃ are both methyl, or R ₂ and R ₃ form cyclohexyl. Even more preferably, R ₂ and R ₃ are both methyl. Even more preferably, R ₂ and R ₃ form cyclohexyl.

R ₄ , R ₅ and R ₆ are preferably independently selected from H, -NO ₂ , methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl , ethenyl, propen-1-yl, buten-1-yl, penten-1-yl, hexen-1-yl, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, sec-butoxy, tert-butoxy , n-pentoxy, n-hexoxy.

Preferably R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , C _1-6 alkyl and C _1-6 alkoxy. R ₄ , R ₅ and R ₆ are preferably independently selected from H, -NO ₂ , methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl , methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, n-hexoxy.

Preferably R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ and C _1-6 alkoxy. More preferably, R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, n- Hexoxy.

Preferably R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , methyl, sec-butyl and methoxy. Preferably R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ and methoxy. Preferred is one of R ₄ , R ₅ and R ₆ -NO ₂ . Preferred are two of R ₄ , R ₅ and R ₆ -NO ₂ .

wobei
R₁ ausgewählt ist aus C_1-6-Alkyl und C_1-6-Hydroxyalkyl.
R₂ und R₃ unabhängig ausgewählt sind aus C_1-6-Alkyl, oder wobei R₂ und R₃ zusammen C₅-C₇-Cycloalkyl bilden;
R₄, R₅ und R₆ unabhängig ausgewählt sind aus H, -NO₂, C_1-6-Alkyl und C_1-6-Alkoxy.
wobei mindestens eines von R₄, R₅ und R₆ -NO₂ ist, mehr bevorzugt wobei eines von R₄, R₅ und R₆ -NO₂ ist.More preferably, the photochromic polymer composition contains a spiropyran of formula (I)

where
R ₁ is selected from C _1-6 alkyl and C _1-6 hydroxyalkyl.
R ₂ and R ₃ are independently selected from C _1-6 alkyl, or where R ₂ and R ₃ together form C ₅ -C ₇ cycloalkyl;
R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , C _1-6 alkyl and C _1-6 alkoxy.
wherein at least one of R ₄ , R ₅ and R ₆ is -NO ₂ , more preferably wherein one of R ₄ , R ₅ and R ₆ is -NO ₂ .

Accordingly, it is preferred that R ₁ is selected from methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, hydroxymethyl, 1-hydroxyethyl, 1- Hydroxypropyl, 2-Hydroxypropyl, 1-Hydroxybutyl, 1-Hydroxypentyl, 1-Hydroxyhexyl. R ₁ is preferably selected from methyl, hexyl and 1-hydroxyethyl.

Preferably R ₂ and R ₃ are independently selected from methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, or R ₂ and R ₃ together form cyclopentyl, cyclohexyl or cycloheptyl.

Preferably R ₂ and R ₃ are both methyl, or R ₂ and R ₃ together form cyclohexyl. Even more preferably, R ₂ and R ₃ are both methyl. Even more preferably, R ₂ and R ₃ together form cyclohexyl.

R ₄ , R ₅ and R ₆ are preferably independently selected from H, -NO ₂ , methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl , methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, n-hexoxy.

Preferably R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ and C _1-6 alkoxy. More preferably, R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, n- Hexoxy.

Preferably R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , methyl, sec-butyl and methoxy. Preferably R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ and methoxy. Preferred are two of R ₄ , R ₅ and R ₆ -NO ₂ .

Most preferably, the spiropyran is selected from the group consisting of:

wobei
R₇ und R_7' beide -CN sind, oder R₇ and R_7' zusammen einen perfluorierten Cyclopentenring bilden;
R₈ and R_8' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl und C_2-6-Alkenyl;
R₉ und R_9' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl, C_2-6-Alkenyl, Phenyl und Benzyl;
R₁₀ und R_10' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl, C_2-6-Alkenyl, Phenyl und Benzyl;
R₁₁ und R_11' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl, C_2-6-Alkenyl, Phenyl und Benzyl;
oder wobei in Formel (IIa) R₉/R₉, and R₁₀/R_10' zusammen einen Benzolring bilden.The photochromic polymer composition preferably comprises a diarylethene of the formula (IIa), (IIb) or (IIc)

where
R ₇ and R _7' are both -CN, or R ₇ and R _7' together form a perfluorinated cyclopentene ring;
R ₈ and R _8' are identical and are selected from H, C _1-6 alkyl and C _2-6 alkenyl;
R ₉ and R _9' are identical and are selected from H, C _1-6 alkyl, C _2-6 alkenyl, phenyl and benzyl;
R ₁₀ and R _10' are identical and are selected from H, C _1-6 alkyl, C _2-6 alkenyl, phenyl and benzyl;
R ₁₁ and R _11' are identical and are selected from H, C _1-6 alkyl, C _2-6 alkenyl, phenyl and benzyl;
or where in formula (IIa) R ₉ /R ₉ , and R ₁₀ /R _10' together form a benzene ring.

The photochromic polymer composition preferably comprises a diarylethene of the formula (IIa). The photochromic polymer composition preferably comprises a diarylethene of the formula (IIb). The photochromic polymer composition preferably comprises a diarylethene of the formula (IIc).

Preferably R ₈ and R _8' are identical and are selected from H and C _1-6 alkyl. More preferably, R ₈ and R _8' are identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, ethenyl, Propen-1-yl, Buten-1-yl, Penten-1-yl and Hexen-1-yl.

More preferably, R ₈ and R _8' are identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl and n-hexyl. Even more preferably, R ₈ and R _8' are identical and are selected from methyl and ethyl. Most preferably, R ₈ and R _8' are identical and are methyl.

Preferably R ₉ and R _9' are identical and are selected from H, C _1-6 alkyl and phenyl. R ₉ and R _9' are preferably identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, ethenyl, propene -1-yl, buten-1-yl, penten-1-yl, hexen-1-yl and phenyl.

Preferably R ₉ and R _9' are identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl and phenyl. Even more preferably, R ₉ and R _9' are identical and are selected from H, methyl and phenyl. Most preferably, R ₉ and R _9' are identical and are selected from methyl and phenyl.

Preferably R ₁₀ and R _10' are identical and are selected from H, C _1-6 alkyl and phenyl. R ₁₀ and R _10' are preferably identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, ethenyl, Propen-1-yl, Buten-1-yl, Penten-1-yl, Hexen-1-yl and Phenyl.

Even more preferably, R ₁₀ and R _10' are identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl and Phenyl. Most preferably, R ₁₀ and R _10' are identical and are selected from H and methyl.

Preferably R ₁₁ and R _11' are identical and are selected from H, C _1-6 alkyl and phenyl. R ₁₁ and R _11' are preferably identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, ethenyl, propene -1-yl, buten-1-yl, penten-1-yl, hexen-1-yl and phenyl.

More preferably, R ₁₁ and R _11' are identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl and phenyl. Even more preferably, R ₁₁ and R _11' are identical and are selected from H or methyl. Most preferably, R ₁₁ and R _11' are identical and are H.

wobei
R₇ und R_7' beide -CN sind, oder R₇ and R_7' zusammen einen perfluorierten Cyclopentenring bilden;
R₈ und R_8' identisch sind und ausgewählt sind aus H und C_1-6-Alkyl;
R₉ und R_9' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl und Phenyl;
R₁₀ und R_10' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl und Phenyl;
R₁₁ und R_11' identisch sind und ausgewählt sind aus H, C_1-6-Alkyl und Phenyl;
oder wobei in Formel (IIa) R₉/R_9' and R₁₀/R_10' zusammen einen Benzolring bilden.The photochromic polymer composition preferably comprises a diarylethene of the formula (IIa), (IIb) or (IIc)

where
R ₇ and R _7' are both -CN, or R ₇ and R _7' together form a perfluorinated cyclopentene ring;
R ₈ and R _8' are identical and are selected from H and C _1-6 alkyl;
R ₉ and R _9' are identical and are selected from H, C _1-6 alkyl and phenyl;
R ₁₀ and R _10' are identical and are selected from H, C _1-6 alkyl and phenyl;
R ₁₁ and R _11' are identical and are selected from H, C _1-6 alkyl and phenyl;
or where in formula (IIa) R ₉ /R _9' and R ₁₀ /R _10' together form a benzene ring.

Accordingly, it is preferred that R ₈ and R _8' are identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl and n-hexyl . More preferably R ₈ and R _8' are identical and are selected from methyl and ethyl, most preferably R ₈ and R _8' are identical and are methyl.

Preferably R ₉ and R _9' are identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl and phenyl. More preferably, R ₉ and R _9' are identical and are selected from H, methyl and phenyl. Even more preferably, R ₉ and R _9' are identical and are selected from methyl and phenyl.

Preferably R ₁₀ and R _10' are identical and are selected from H, C _1-6 alkyl and phenyl. More preferably, R ₁₀ and R _10' are identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl and phenyl . More preferably, R ₁₀ and R _10' are identical and are selected from H and methyl.

R ₁₁ and R _11' are preferably identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl and phenyl. More preferably, R ₁₁ and R _11' are identical and are selected from H or methyl. Even more preferably, R ₁₁ and R _11' are identical and are methyl. Even more preferably, R ₁₁ and R _11' are identical and are H.

Most preferably, the spiropyran is selected from the group consisting of:

Most preferably, the diarylethene is selected from the group consisting of:

Preferably the photochromic compound is in an amount of 0.01 to 5.00% by weight, more preferably in an amount of 0.01 to 2.00% by weight, even more preferably in an amount of 0.01 to 0.90% by weight, more preferably in an amount of 0.01 to 0.60% by weight, most preferably in an amount of 0.03 to 0.60% by weight, based on the total weight the photochromic polymer composition.

Preferably the spiropyran is in an amount of 0.01 to 5.00% by weight, more preferably 0.01 to 2.00% by weight, even more preferably in an amount of 0.01 to 0.90% by weight. -%, even more preferably in an amount of 0.01 to 0.60% by weight, most preferably in an amount of 0.10 to 0.60% by weight, based on the total weight of the photochromic polymer composition .

Preferably the diarylethene is in an amount of 0.01 to 10.00% by weight, more preferably from 0.01 to 5.00% by weight, more preferably from 0.01 to 2.00% by weight, even more preferably from 0.01 to 0.90 wt.%, even more preferably from 0.03 to 0.60 wt.%, even more preferably from 0.08 to 0.60 wt.%, am most preferably from 0.10 to 0.60% by weight, based on the total weight of the photochromic polymer composition.

It is preferred that the composition be free of volatile organic compounds (VOC). Preferably the composition comprises 0.05% by weight or less, more preferably 0.01% by weight or less of VOC, based on the total amount of the composition.

Excipients

It is further preferred that the composition of the present invention comprises one or more excipients. Auxiliary substances can be selected from the group consisting of antioxidants, UV absorbers, light stabilizers, plasticizers, impact modifiers, flame retardants, clarifying agents, antistatic agents, lubricants, antimicrobial agents and mixtures thereof.

The auxiliaries are preferred in an amount of 0.1 to 3.0% by weight, preferably 0.1 to 2.0% by weight, more preferably 0.1 to 0.5% by weight, based on Total amount of photochromic polymer composition included.

Articles comprising the composition of the present invention

The first industrial application of photochromic chemicals was in the eyewear industry with photochromic lenses. The properties sought were rapid photoactivation and deactivation depending on the light and high fatigue resistance. Silver-based compounds were a good solution. However, with the transition to organic lenses, T-type organic photochromic compounds, such as B. Spiropyrans, Spirooxazines and Naphthopyrans, further developed. These compounds are also used in other areas by incorporating them into paints, varnishes, inks or textiles ( Yoon B et al., J Mater Chem C, 2013, 1, 2388-2403 ; Parhizkar M, Zhao, Y, Lin T, Photochromic Fibers and Fabrics in Tao X (Ed.), Handbook of Smart Textiles, Springer Singapore, Singapore, 2014, pp. 1-23 ).

Organic photochromic compounds are also used as color, correction or polarization filters. But they are also used for the transport and release of target molecules ( Lerch MM et al., Chem Soc Rev, 2018, 47, 1910-1937 ). With the development of P-type photochromic compounds such as B. Diarylthenes, further applications have emerged, such as. B. Holography, optical data storage and optical switches ( Kawata S & Kawata Y, Chem Rev, 2000, 100, 1777-1788 ; Tian H & Feng Y, J Mater Chem, 2008, 18, 1617-1622; Yokoyama Y, Chem Rev, 2000, 100, 1717-1739 ). These applications require stability of both chemical forms over time. More recently, organic photochromic compounds are being used for medical diagnostics and super-resolution imaging ( Cheng H et al., Coord Chem Rev, 2018, 372, 66-84 ). In addition to their tunable optical properties, these compounds can be used to create macroscopic mechanical systems by changing conformations and bond lengths ( Ohshima S et al., Chem Sci, 2015, 6, 5746-5752 ).

The present invention therefore also relates to an article comprising the composition of the present invention. The article is preferably an injection molded article. Although any shape is conceivable, the article is preferably in the form of a film, a plate or a panel.

Preferably the films, plates or panels are suitable for use as automotive parts. Thus, it is preferred that the article is a vehicle part, preferably a windshield, a portion of an instrument panel, a door panel or a center console.

It is further preferred that the article has a light transmittance of 7% or less, as determined by DIN EN ISO 13468-1 , 2 with lighting or after DIN EN ISO 8980-1 .

Methods for producing compositions and articles

Numerous studies are investigating the properties of photochromic molecules in solution. However, for most applications it is necessary to develop materials with photochromic properties. Incorporating photochromic molecules into solid matrices can then change the photochromic properties of these matrices (Smets G, Photochromic phenomena in the solid phase, in Unusual Properties of New Polymers, Springer Verlag, Berlin/Heidelberg, 1983, pp. 17-44).

For this purpose, photochromic compounds can be crystallized in solid form for use in particular in optoelectronics ( Benard S & Yu P, Adv Mater, 2000, 12, 48-50 ; Weerasekara RK et al. Cryst Growth Des, 2017, 17, 3040-3047 ; Morimoto M et al, JACS, 2003, 125, 11080-11087 ). Diarylethenes have been studied particularly in crystalline form because in this form they have properties suitable for applications ( Irie M et al., Chem Rev, 2014, 114, 12174-12277 ; Morimoto M & irie M, Chem Commun, 2005, 3895-3905). Inorganic compounds are widely used for inorganic materials such as glass in the eyewear industry ( Morimoto M & Irie M, Chem Commun, 2005, 3895-3905 ; Morimoto S & Mishima M, J Non-Cryst Solids, 1980, 42, 231-238; He T & Yao J, Prog Mater Sci, 2006, 51, 810-879 ). But organic compounds have also been incorporated into inorganic matrices to form so-called hybrid materials in which the nature of the matrix differs from the photochromic compound ( Kinashi K et al., Thin Solid Films, 2008, 516, 2532-2536 ; Pardo R et al, Chem Soc Rev, 2011, 40, 672-687 , Preston D, J Phys Chem, 1990, 94, 4167-4172 ).

Nevertheless, polymeric materials are used in a large proportion of applications. You can choose from different categories such as: B. Composites or liquid crystals occur ( Yitzchaik S, Macromolecules, 1990, 23, 707-713, Ramesbabu, K et al., J Phys Chem B, 2011, 115, 3409-3415; Frigoli M & Mehl GH, Chem EurJ, 2004, 10, 5243-52509). The structures of the photochromic compounds can therefore be directly part of the polymer chain, either in the main chain or in the side chains (Pariani G et al., J Mater Chem, 2011, 21, 13223-13231; Bu J et al, Nat Commun, 2014, 5, 3799 ). This requires suitable synthetic means and often enables the production of nanoparticles or thermosets. Photochromic compounds can also be mixed directly with the resins before polymerization. These resins can then be photopolymerized ( Hoo Lee B et al., Dyes Pigm, 2004, 61, 235-242; Punpongsanon P et al., Recoloring 3D Printed Objects Using Photochromic Inks, in: Proceedings of the 2018, CHI Conference on Human Factors in Computing Systems, ACM, Montreal QC Canada, 2018, pp. 1-12 ). However, this polymerization route would be very expensive to develop in-house.

To produce thermoplastics with photochromic properties, the compounds are often incorporated after polymerization by solubilization with the thermoplastics ( Zheng C et al, Dyes Pigm, 2013, 98, 565-574; Yoshida T et al., J Photochem Photobiol A: Chem, 1996, 95, 265-270; Bahajaj AA et al., Pigment & Resin Technology, 2010, 39, 71-76; Richer R, Chem Phys, 1988, 122, 455-452 ). Then the solvent is evaporated and a film is formed. The solvent-based process generally produces polymeric films. It is not possible to obtain geometrically complex parts. Additionally, this process involves volatile organic compounds (VOCs) that should not be used in industrial environments. The compounds can also be used with a supercritical fluid, such as. B. supercritical CO ₂ , or ethanol can be impregnated into the materials ( Solovieva AB et al., J Mol Liq, 2017, 239, 74-82; Bhran AAEK, Etude de Ia fonctionnalisation de polyurethane: effet du spiropyranne sur leurs proprietes optiques et mecaniques, Nancy Universite, 2011; Abate MT, Dyes Pigm, 2020, 183, 108671 ). However, this technique is only used for films and requires special experimental conditions, such as: B. Vacuum.

Only a few works have attempted to produce thermoplastics with photochromic properties through thermal processes such as B. Compounding and injection molding (Li et al., New J Chem, 2018, 42, 10885-10890; Micciche et al., J Polym Sci B Polym Phys, 2016, 54, 1593-1601; Optov et al., Polym Sci Ser B, 2018), also because the light-sensitive molecules can be broken down at the high temperatures required for these processes.

In addition, the photochromic compounds can be in the form of nanoparticles. This combination of photochromic compounds with a polymeric or inorganic coating can improve the thermal stability of the photosensitive compounds ( Zhou Y et al, Sens Actuators B Chem, 2013, 188, 502-512; He Z et al., Colloids Surf A, 2020, 594, 124661; Evans RA et al, Nat Mater, 2005, 4, 249-253; Julia-Lopez A et al, ACS Appl Mater Interfaces, 2019, 11, 11884-11892 ). Around ten pigments from four different suppliers were then incorporated into PMMA and PC through compounding. These compounds consisted of T-type photochromic organic molecules encapsulated either in a polymer matrix of polystyrene, oxymethylene, and xylene or in a mineral matrix of silica, potassium nitrate, and sodium. These pigments then showed very poor solubility, which was characterized by a milky appearance of the material. Furthermore, the decolorization kinetics of this type of compound is too fast to observe the color change of the material after irradiation (less than a second) (data not shown).

Accordingly, the present invention further relates to a method for producing the photochromic composition, the method comprising compounding PC or PMMA and a photochromic compound to form the thermoplastic composition.

The compounding can be carried out according to methods known in the art. The person skilled in the art will know how to select the appropriate technique or device depending on e.g. B. can select the scale and polymer used.

The compounding is preferably carried out at a temperature in the range from 180 to 230 ° C. The composition of the present invention is preferably provided in the form of granules.

The process for producing the article according to the invention is preferably carried out in the absence of volatile organic components (VOC).

The present invention further relates to the manufacture of an article comprising the composition of the present invention, the process comprising compounding of PC or PMMA and a photochromic compound to form the thermoplastic composition, followed by injecting and molding the thermoplastic composition into the article.

The mixing, injection and pouring can be carried out using methods known in the prior art. The person skilled in the art will know how to select the appropriate technique or device, e.g. B. can be selected depending on the size, the polymer used or the desired final shape of the article.

Preferably, the compounding in the process for producing the article is carried out at a temperature in the range of 180 to 230°C. The injection to produce the article is preferably carried out at a temperature gradient in the range of 220 to 350 ° C. Preferably, the molding to produce the article is carried out at a temperature in the range of 80 to 120°C.

The process for producing the article according to the invention is preferably carried out in the absence of volatile organic components (VOC).

characters

• 1 : Schematic representation of an injection device with cylinder and injection screw with temperature zones 1, 2, 3, 4 and 11 and shape.
• 2 : Properties of T-type organic photochromic compounds in PMMA and PC at various concentrations; the colors are shown before and after irradiation with LED at 365 nm for 1 minute.
• 3 : Appearance of granules and plates made of a) PMMA containing 0.05 wt% SP0 and b) PC containing 0.04 wt% SP0, depending on the residence time in the cylinder during the injection process.
• 4 : Appearance of the SPO-containing PMMA and PC samples after 500 hours in the dark at 100 °C. Compounded PMMA and PC samples without SPO, compounded and sprayed PMMA samples each comprising 0.05 wt% SPO, and compounded and sprayed PC samples each comprising 0.04 wt% SPO are with the compared to corresponding unaged samples.
• 5 : Photochemical coloring and decoloring times of SP0 depending on the thermoplastic type; a) 0.05% by weight SP0 in PMMA; 0.04% by weight SP0 in PC.
• 6 : Photochemical coloring and decolorizing times of SP0 depending on the SP0 concentration; a) 0.03% by weight SP0 in PC; b) 0.04% by weight SP0 in PC.
• 7 : Coloring after irradiation of PC samples comprising a) 0.02% by weight and b) 0.12% by weight SP0 depending on the irradiation time with LED at 365 nm.
• 8th : Absorption of PC samples comprising 0.02 wt.% and 0.12 wt.% SP0 at 595.6 nm depending on the time under irradiation with LED at 365 nm and then with LED at 525 nm.
• 9 : Absorption at 595.6 nm of PC samples containing 0.02 wt.% and 0.12 wt.% SP0 a) during photodecolorization and b) during thermal decolorization.
• 10 : a) Absorption at 595.6 nm of a PC sample comprising 0.02 wt.% and 0.12 wt.% SP0 during irradiation cycles with LED at 365 nm and LED at 525 nm and b) Color of a PC sample containing 0.12% by weight SP0 during irradiation cycles with LED at 365 nm and LED at 525 nm.
• 11 : a) 2.5 mm thick PC spray plate comprising 0.04 wt.% SP0 after 5 seconds of irradiation with LED at 365, b) color change over the entire thickness of a 2.5 mm thick PC spray plate containing 0.04 wt .-% SP0 and c) writing with laser at 409 nm on a 2.5 mm thick PC plate containing 0.04 wt.% SP0.
• 12 : 2.5 mm thick PC spray plate with a mask (left) and writing after 10 seconds of irradiation with an LED projector at 395 nmr (right).
• 13 : PC plate of 2.5 mm thickness a) before and b) after irradiation with an LED projector at 395 nm and c) inscriptions after photodecolorization with LED at 525 nm and a mask (top) and with a laser at 532 nm (below).
• 14 . Appearance of PC samples containing 0.04% by weight SPO, which are injected into the cylinder at a) 230 ° C and b) 300 ° C on a laboratory scale after different times.
• 15 : Properties of P-type organic photochromic compounds at various concentrations in PMMA and PC, colors are shown before and after irradiation with LED at 365 nm for 1 minute.
• 16 : Color stability of diarylethenes in PMMA and PC over time.
• 17 : Appearance of PC samples containing diarylethenes at different concentrations depending on the residence time in the cylinder during the injection process.
• 18 : Transmittance of PC samples comprising DAE obtained after 5 minutes residence time in the cylinder; 0.2% (DAE1 + DAE3) denotes a sample comprising 0.1 wt% DAE1 and 0.1 wt% DAE3; 0.5% (DAE1 + DAE3) refers to a sample comprising 0.25 wt% DAE1 and 0.25 wt% DAE3.
• 19 : Coloring of PC samples containing diarylethene depending on the irradiation time with LED at 365 nm; 0.2% (DAE1 + DAE3) denotes a sample comprising 0.1 wt% DAE1 and 0.1 wt% DAE3; 0.5% (DAE1 + DAE3) refers to a sample comprising 0.25 wt% DAE1 and 0.25 wt% DAE3.
• 20 : Absorption depending on the irradiation time for PC samples containing diarylethene; 0.2% (DAE1 + DAE3) denotes a sample comprising 0.1 wt% DAE1 and 0.1 wt% DAE3; 0.5% (DAE1 + DAE3) refers to a sample comprising 0.25 wt% DAE1 and 0.25 wt% DAE3.
• 21 : Transmittance of PC samples containing diarylethenes before irradiation, after 1 second irradiation and after various longer irradiation times with LED at 365nm at tAmax.
• 22 . Transmittance dependent on wavelength for PC samples containing 0.5 wt.% diarylethene after an irradiation time equal to tAmax; 0.5% (DAE1 + DAE3) refers to a sample comprising 0.25 wt% DAE1 and 0.25 wt% DAE3.
• 23 : Color dependent on the irradiation time with LED at 365 nm of PC samples containing diarylethenes in the L*a*b* reference frame (white are the concentrations at 0.1 wt% or 0.2 wt% and black the concentrations at 0.5% by weight.
• 24 : Brightness (L*) of PC samples containing diarylethenes depending on the irradiation time with the LED at 365nm; 0.2% (DAE1 + DAE3) denotes a sample comprising 0.1 wt% DAE1 and 0.1 wt% DAE3; 0.5% (DAE1 + DAE3) refers to a sample comprising 0.25 wt% DAE1 and 0.25 wt% DAE3.
• 25 : Color change of PC samples comprising diarylethenes after 500 hours in the oven at 100 °C; 0.2% (DAE1 + DAE3) denotes a sample comprising 0.1 wt% DAE1 and 0.1 wt% DAE3; 0.5% (DAE1 + DAE3) refers to a sample comprising 0.25 wt% DAE1 and 0.25 wt% DAE3.
• 26 : Δb* depending on the aging time for non-irradiated zones of PC samples containing diarylethenes and for a commercial PC sample without diarylethenes as a reference; 0.2% (DAE1 + DAE3) denotes a sample comprising 0.1 wt% DAE1 and 0.1 wt% DAE3; 0.5% (DAE1 + DAE3) refers to a sample comprising 0.25 wt% DAE1 and 0.25 wt% DAE3.
• 27 : ΔE of the irradiated zones depending on the aging time for diarylethene-containing PC samples; 0.2% (DAE1 + DAE3) denotes a sample comprising 0.1 wt% DAE1 and 0.1 wt% DAE3; 0.5% (DAE1 + DAE3) refers to a sample comprising 0.25 wt% DAE1 and 0.25 wt% DAE3.
• 28 : PC pellets; a) commercially available, b) commercially available after extrusion, comprising diarylethenes, c) compounded with 0.25% by weight of DAE1 and 0.25% by weight of DAE3.
• 29 : PC injection panels made from a) commercial pellets, b) commercial pellets extruded once on the semi-industrial device, c) pellets prepared with 0.25 wt% DAE1 and 0.25 wt% DAE3 be compounded in the semi-industrial device.
• 30 : PC injection plate comprising 0.25% by weight of DAE1 and 0.25% by weight of DAE3 a) before irradiation, after 2 minutes of irradiation with LED at 395 nm and after 1 minute of irradiation with LED at 525 nm and b) before irradiation and after writing with a laser at 405 nm.
• 31 : Dyeing PC samples comprising 0.25 wt% DAE1 and 0.25 wt% DAE3 upon irradiation with the LED at 365 nm for a thickness of a) 1.0 mm and b) 2.5 mm .
• 32 : Absorption at 570 nm depending on the irradiation time with LED at 365 nm for PC samples comprising 0.25 wt% DAE1 and 0.25 wt% DAE3 of 1.0 mm and 2.5 mm thickness, respectively.
• 33 : Color development in the L*a*b* frame depending on the irradiation time with LED at 365 nm of PC samples comprising 0.25 wt% DAE1 and 0.25 wt% DAE3 of 1 mm and 2, 5mm thickness.
• 34 : a) Saturation C*, b) Brightness L* of 1.0 mm and 2.5 mm PC samples containing 0.25 wt% DAE1 and 0.25 wt% DAE3, depending on the irradiation time with the LED at 365 nm.
• 35 . Color change of 2.5 mm PC samples containing 0.25 wt% DAE1 and 0.25 wt% DAE after 500 h in the oven at 100 °C.

Examples

Materials and methods

Polymers

The following PMMA and PC starting materials were used: polymer Trade name Light transmittance between 380 and 780 nm (%) Glass transition temperature Tg (°C) PMMA Plexiglas® Heatresist FT15, Röhm, DE 91% 121 PC Makrolon® 2207, Covestro, DE 89% 144

Compounding

Unless otherwise stated, compounding was performed as follows.

On a laboratory scale, a HAAKETM MiniLab Micro Compounder was used, which can hold approx. 3 g of material. The extruder was equipped with two non-mesh, double-threaded, regular-pitch conical screws that rotated in unison. The extrusion temperatures were set at 190 °C for PMMA and 210 °C for PC.

Formulations of 10 g of photochromic thermoplastics were prepared. The photochromic product powder was mixed with the thermoplastic granules directly in the compounding machine to avoid material losses. The number of passes of the mixture through the compounder was set to 2 to limit decomposition.

On a semi-industrial scale, a HAAKETM Rheomex CTW100 QC compounder equipped with counter-rotating, interpenetrating conical screws was used. The extrusion temperatures were set at 200 to 210 °C for both PMMA and PC.

Formulations of 5 to 15 kg of photochromic thermoplastics have been produced on a semi-industrial scale. Premixing of the photochromic product powder in a tenfold concentration in wt .% based on its final mass concentration with the thermoplastic granules was carried out manually. The premix was mixed in one pass to obtain a main batch. For the final photochromic thermoplastic, 10% by weight of the masterbatch and 90% by weight of the thermoplastic granules were compounded in a second pass to form the final formulation.

Injection molding

Unless otherwise stated, injection molding was carried out as follows.

On the laboratory scale, a HAAKETM MiniJet PRO press was used, a vertical injection molding device that can be connected to the HAAKETM MiniLab Micro compounder mentioned above.

Unless otherwise stated, the injection pressure is set to its maximum, ie 800 bar, for rapid injection. The holding pressure was 400 bar and the injection and holding pressure times were 5 seconds each for PMMA and PC samples. The cylinder temperature of the injection unit was for Spiro pyran set to 230 °C. For the more temperature-stable diarylethenes, the cylinder temperature was increased to up to 280 °C. The temperature in the molding system was set to 120 °C.

Spiropyran samples measuring approximately 25.0 x 10.0 mm and 1 mm thick and diarylethene samples measuring approximately 50.0 x 10.0 mm and 1 mm thick were obtained.

On a semi-industrial scale, the Krauss-Maffei 160T injection molding machine with a capacity of 160 t was used. Before injection, the granules can be dried overnight at 120 °C.

The injection molding device was equipped with a single screw, which provided additional heating and a temperature gradient with five temperature zones ( 1 ).

The rotation speed of the injection screw was set to 100 rpm. set. For the production of spiropyran or diarylethylene formulations, individual temperature gradients were applied to the screw barrel.

The cycle time was 30 to 40 seconds and the mold temperature was 80 °C for spiropyrans and 90 °C for diarylethenes. The panels, measuring approximately 167.0 x 84.5 mm and 2.5 mm thick, were manufactured on a semi-industrial scale.

Light activation

Photochromic thermoplastics were photoreactivated under irradiation with a light source. The following devices were used: abbreviation Emission wavelength Irradiance UV LED Hamamatsu LIGHTNINGCURE® LC-L1 LED at 365 nm 365 nM 315 to 1000 mW/ ^cm2 TaoYuan China LED at 395 nm 395 nM 100 mW/ ^cm2 3P Gold Laser KYSON for Bachin Machine Laser at 409 nm 409 nM 10 to 400 mW HighPower Solis®-525C LED LED at 525 nm 525 nM 1000 mW/ ^cm2

Thermal analysis

• Unter N₂ (100 ml/Min)
• (1) 0 °C; 5 Min
• (2) 0-250 °C; 10 °C/Min
• (3) 250 °C; 5 Min
• (4) 250-0 °C; -10 °C/Min
• (5) 0 °C; 5 Min
• (6) 0-250 °C; 10 °C/Min

The glass transition temperature (Tg) of thermoplastics with and without photochromes was measured using a differential calorimeter (DSC) Metler Toledo STARe System DSC 1. Several milligrams of thermoplastic granules are examined in an aluminum crucible using the following analytical procedure:

• Under N ₂ (100 ml/min)
• (1) 0°C; 5 mins
• (2) 0-250°C; 10°C/min
• (3) 250°C; 5 mins
• (4) 250-0°C; -10°C/min
• (5) 0°C; 5 mins
• (6) 0-250°C; 10°C/min

The glass transition temperature Tg was determined from the observed decrease in heat flow using the obtained DSC curves.

The thermal stability of the photochromic compounds was determined by thermogravimetric analysis (TGA) using a Mettler Toledo STARe System TGA/DSC 3+ thermal analyzer.

A few milligrams of the photochromic powder were placed in ceramic crucibles, which were subjected to a temperature ramp from 30 to 600 °C with an increase of 10 °C per minute under nitrogen.

Two temperatures were recorded for each sample: the temperature corresponding to a 10% mass loss and the temperature corresponding to the first minimum of the mass loss derivative, which represents the temperature at the inflection point of the mass loss curve. This latter temperature is called the decomposition temperature.

UV-VIS spectroscopy

The optical properties of the thermoplastics with and without photochromic compounds as well as the photochromic compounds were analyzed using a JASCO V750 visible UV spectrophotometer.

The spectrophotometer has been expanded with an additional module so that the SpectraManager software can also enter the colorimetric data of the sample, in particular the L*, a* and b* values. These quantities are derived from the CIELAB model introduced by the International Commission on Illumination (CIE) in 1976. This is an international model that is independent of the measuring device and is based on human color perception. It is represented as a spherical space, where L* is the neutral axis, which corresponds to brightness, black at 0% and white at 100%, and the axes a* and b*, which correspond to chromaticity, where a* is green to red and b* ranges from blue to yellow,

Anhand der L*a*b*-Daten lässt sich die Farbe einer Probe mit einer Referenz vergleichen. Zu diesem Zweck werden andere Werte eingeführt: ΔL*, Δa*, Δb*. Sie entsprechen der Differenz zwischen dem Wert der Probe und dem der Referenz. Die Interpretationen des Vorzeichens dieser Werte für eine Probe sind in Tabelle 1 unten dargestellt. Tabelle 1: Interpretation des Vorzeichens von ΔL*, Δa* und Δb* für eine analysierte Probe. ΔL* Δa* Δb* positiv + klar + rot + gelb negativ + dunkel + grün + blau It is therefore possible to characterize a color using the values L*, a* and b*. In addition, the saturation value C*, which corresponds to the distance between the neutral point and the measurement point, and the hue h°, which corresponds to the angle between the positive axis a* and the half-line C*, can be evaluated. These two values can then be expressed as follows: $$C*=\sqrt{a{*}^2+b{*}^2}H°=\text{arctan}\frac{b*}{a*}$$

The L*a*b* data can be used to compare the color of a sample to a reference. For this purpose, other values are introduced: ΔL*, Δa*, Δb*. They correspond to the difference between the value of the sample and that of the reference. Interpretations of the sign of these values for a sample are presented in Table 1 below. Table 1: Interpretation of the sign of ΔL*, Δa* and Δb* for an analyzed sample. ΔL* Δa* Δb* positive + clear + red + yellow negative + dark + green + blue

The overall color difference of a sample compared to a reference can be defined as a single quantity ΔE: $$\Delta E=\sqrt{{\left(\Delta L*\right)}^2+{\left(\Delta a*\right)}^2+{\left(\Delta b*\right)}^2}$$

This value can be used to determine the perception threshold and the acceptance threshold, which correspond to the minimum color difference perceivable by the eye and the application-specific maximum acceptable color difference.

As part of the development of the new thermoplastic, the value ΔE is used for the color stability of the samples during the aging tests and when evaluating the effects of the addition of a photochromic compound on the initial color (without activation) of the thermoplastic sample. A color is considered stable if the ΔE value is less than or equal to 2.

Example 1 - Type T Organic Compounds

Spiropyrans used

For the study of reversible systems, 10 spiropyrans, designated SP0 to SP9, of the general structure indolinobenzospiropyran with variable substituents on the benzopyran ring were selected (Table 2).

1',3'-Dihydro-8-methoxy-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-[2H]indol] SP1

1-(2-Hydroxyethyl)-3,3-dimethylindolino-6'-nitrobenzopyrylospiran SP2

1,3,3-Trimethylindolino-7'-nitrobenzopyrylospiran SP3

1-Hexyl,2-cyclohexyl-indolino-7'-nitrobenzopyrylospiran SP4

1,3,3-Trimethylindolinobenzopyrylospira n SP5

1,3,3-Trimethylindolino-β-naphthopyrylospiran SP6

1,3,3-Trimethylindolino-7'-methylbenzopyrylospiran SP7

1,3,3-Trimethylindolino-6'-8'-tertiobutylobenzopyrylospiran SP8

1,3,3-Trimethylindolino-7'-diethylaminobenzopyrylospiran SP9

SP5 to SP9 serve as comparative examples. SP5 to SP9 were determined to have unsatisfactory photoreactivity with no or little visible coloration after UV irradiation and thus did not meet the desired key criteria, i.e. solubility, stability during processing and rapid photoreactivity in thermoplastic matrices. Table 2: Investigated photochromic organic compounds of type T. Surname Abbreviation 9 formula 1,3,3-Trimethylindolino-6'-nitrobenzopyrylospirane SP0

1',3'-Dihydro-8-methoxy-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-[2H]indole] SP1

1-(2-Hydroxyethyl)-3,3-dimethylindolino-6'-nitrobenzopyrylospirane SP2

1,3,3-Trimethylindolino-7'-nitrobenzopyrylospirane SP3

1-Hexyl,2-cyclohexyl-indolino-7'-nitrobenzopyrylospirane SP4

1,3,3-Trimethylindolinobenzopyrylospira n SP5

1,3,3-Trimethylindolino-β-naphthopyrylospiran SP6

1,3,3-Trimethylindolino-7'-methylbenzopyrylospirane SP7

1,3,3-Trimethylindolino-6'-8'-tertiobutylobenzopyrylospirane SP8

1,3,3-Trimethylindolino-7'-diethylaminobenzopyrylospirane SP9

Thermal stability

The thermal stability of the selected additives was evaluated using thermogravimetric analysis. Stability up to 250 °C, or at least 210 °C for PMMA and at least 190 °C for PC, is desired in order to incorporate the additives into thermoplastics, such as. B. PMMA and PC to enable. Table 3 summarizes the temperatures at which 10% weight loss occurs and the decomposition temperatures of the compounds used. Table 3: Characteristic decomposition temperatures of photochromic compounds of type T. links Temperature at which 10% weight loss occurs (°C) Decomposition temperature (°C) SPO 260 270 SP1 254 256 SP2 246 251 SP3 266 268 SP4 276 296 SP5 235 299 SP6 261 324 SP7 178 228 SP8 244 334 SP9 175 282

Compounding

The photochromic compounds were treated with PMMA and PC at 190 °C and 210 °C, respectively, in the range of 0.02 to 0.06 wt% based on the total amount of the composition, as indicated in 2 , mixed using the HAAKETM MiniLab Micro compounder. These temperatures produce a slightly viscous and homogeneous thermoplastic at the exit of the extruder and at the same time limit the decomposition of the photochromic compounds of type T. The screw speed was 50 rpm.

The spiropyrans were all easily miscible with PMMA and PC. A slight pink hue was observed for spiropyrans in PMMA after compounding, which disappears at room temperature. This was also observed for SP2 in PC, while SP1 in PC has a slightly bluish initial color that later disappeared. SP5 showed no initial color in PMMA. SP0 and SP4 were also transparent in PC. As expected from the thermal analysis, SP7 showed a yellowish color, which was characteristic of compound decomposition, and SP9 colored the PMMA strongly pink at a low concentration of 0.05 wt% after compounding.

Photoreactivity after compounding

After compounding, the photoreactivity of the photochromic compounds was observed under irradiation with an LED 315 mW/cm ² at 365 nm for 1 minute ( 2 ).

A wide variety of initial appearances could be observed. Only spiropyrans containing a -NO ₂ group (SP0 to SP4) showed a color change after 1 min of irradiation with the LED at 365 nm. These spiropyrans changed from colorless/pink to blue. These results show that it is possible to achieve a very distinct color with very low concentrations of additives such as: B. 0.02% by weight, based on the total amount of the composition.

Without being bound by theory, it is believed that the nature of the substituents will influence the electronic behavior of the molecule. Depending on the type of substituent present on the molecule, donor or attractor, ring opening occurs either through a singlet state or through a triplet state. The attractive groups on the pyranic part of the molecule stabilize the merocyanine form ( Chernyshev AV et al., J Photochem Photobiol A Chem, 1019, 378, 201-210) and favored gen the transition to the triplet state (Kolmanskii AS et al., Russ Chem Rev, 1981, 50, 305-315 ). In particular, the nitro group, -NO ₂ , completely alters the photocoloring mechanism by modifying the energy states of spiropyran as well as all mesomeric forms of merocyanine ( Kortekaas L, J Phys Chem, 2018, 122, 6423-6430 ).

A special mechanism has even been demonstrated for nitro-substituted molecules. The absorption band of spiropyran between 300 and 400 nm corresponds to the absorption of the benzopyran moiety. This is the π-π* electronic transition of benzene. Thus, by irradiation at 365 nm and in the presence of an attractive group on the benzene moiety, an intramolecular charge transfer takes place from the oxygen to the attractive group and in particular to the nitro group, in which a π|-π*πn* transition occurs.

This redistribution of the electron density of the molecule leads to a positive charge on the oxygen as well as a polarization of the Cspiro-O bond, which then breaks ( Kolmanskii AS et al., Russ Chem Rev, 1981, 50, 305-315 ). In the absence of the nitro group, after the π-π* electronic transition of benzene, an n-π* transition involving the n-orbital of oxygen can occur under the influence of the indole moiety and/or the environment of the molecule ( Kolmanskii AS & Dyumaev KM, Russ Chem Rev, 1987, 56, 136-151 ). This difference can then explain the lack of photoreaction for molecules from SP5 to SP9.

The rapid color change from SP0 to SP4 molecules is due to the -NO ₂ group, which can stabilize the alkoxy anion and accelerate the rupture of the Cspiro-O bond. Although the efficiency of photoisomerization also depends on the position of the nitro group ( Lee S et al., BKCS, 2012, 33, 3740-3744 ), the presence of the nitro group increases the quantum yield of photostaining by at least twofold by increasing the quantum yield of intersystem crossing. However, the homolytic disruption by the triplet state leads to the formation of a biradical and singlet oxygen, which causes the oxidative decomposition of the substituted nitro-spiropyran. This phenomenon does not occur in the absence of a nitro group with ring opening by heterolytic cleavage through the excited singlet state. Molecules that do not contain nitro groups then show better stability in the presence of oxygen ( Such G, et al., J Macromol Sci Part C Polym Rev, 2003, 43, 547-579; Gautron R et al., Bull Soc Chim Belg, 2010, 100, 315-328 ).

Example 2 - Stability of 1,3,3-trimethylindolino-6'-nitrobenzopyrylospirane (SP0)

As described above in Materials and Methods for Laboratory-Scale Manufacturing, SP0 was compounded into the PMMA at 190 °C and into the PC at 210 °C. During the compounding phase, a thermochromic phenomenon was observed for both thermoplastic matrices, where the color changes from colorless to light purple/pink for PMMA and light blue for PC. The color disappeared after a few minutes when the extrudates returned to room temperature. Two passes were made through the laboratory compounder HAAKETM MiniLab Micro Compounder to obtain a homogeneous mixture. At the end of the compounding process, the mixture was cut into pellets, which were then pressed using the HAAKETM MiniJet PRO press. Table 4 summarizes the concentrations and parameters used. Table 4: Experimental parameters for laboratory-scale production of PMMA and PC samples containing SP0 Thermoplastics Conc .SP0 (wt.%) extrusion injection Temperature (°C) Screw speed (rpm) Injection pressure (bar) Holding pressure (bar) Cylinder temperature (°C) Mold temperature (°C) PMMA 0.05 190 50 800 400 230 110 PC 0.04 210 50 800 400 230 140

For industrial injection molding production, the material must remain stable for 15 minutes at the high compounding and extrusion temperatures.

The PMMA samples obtained showed a slight pink sheen and turned light orange after about 15 minutes in the cylinder at 230 °C, while the PC samples only showed a very slight blue sheen after 15 minutes and then a pinkish-orange color after more than 20 minutes in the cylinder at the same temperature showed ( 3 ). PC in particular seemed well suited for an industrial application.

The incorporation of new compounds into the thermoplastic matrices could impact the final properties of the material, such as: B. the glass transition temperature (Tg). This change could then be indicative of a change in the mechanical properties of the material. To determine the influence of SP0 on the Tg of PMMA and PC, previously compounded pellets containing 0.05 wt% SP0 in PMMA and 0.04 wt% in PC were analyzed using differential scanning calorimetry (DSC). and compared with commercial pellets and commercial pellets extruded without spiropyran. The DSC-Tg values for the twice-compounded and once-extruded samples were identical to SP0 and were close to the values of the commercial samples (Table 5). These temperatures obtained for each sample showed that compounding with SP0 had no significant influence on the Tg of PMMA and PC. The binding of SP0 did not lead to a change in the mobility of the polymer chains. Table 5. Glass transition temperature (Tg) for PMMA and PC before and after compounding at 190 °C and 210 °C, the compounded PMMA samples comprised 0.05 wt% SP0 and the compounded PC samples comprised 0.04 wt. -% SP0 sample Commercially available, Tg (°C) Commercially available, 1 extrusion cycle no photochromic compound, Tg (°C) Commercially available + SP0, 2 compounding cycles, Tg (°C) PMMA 116 120 120 PC 144 145 145

The DSC-Tg values for the samples extruded once without photochromic compound and the samples compounded twice including photochromic compounds are identical and are close to the values of the commercial samples. The temperatures obtained for each sample show that compounding with SP0 has no significant influence on the Tg of PMMA and PC.

Additionally, the effect of adding SP0 to thermoplastics on yellowing behavior over time was examined by accelerated aging in the dark in an oven at 100 °C for 500 hours. Compounded PMMA and PC samples without SP0, compounded and sprayed PMMA samples each comprising 0.05 wt% SP0 and compounded and sprayed PC samples each comprising 0.04 wt% SP0 were produced and aged . The aged samples were visually compared with the corresponding unaged samples ( 4 ).

Slight yellowing was observed for both PMMA samples containing SP0, while no yellowing was observed for the compounded PC containing SP0. The sprayed PC sample containing SP0 had a slight pink color.

Example 3 - Parameters for determining the photoactivity of 1,3,3-trimethylindolino-6'-nitrobenzopyrylospirane (SP0)

Various parameters can influence the kinetics of coloring and decoloring of photochromic molecules, especially the type of thermoplastic and the concentration of the photochromic compound.

PMMA comprising 0.05 wt.% and PC comprising 0.04 wt.% SP0 were compounded as indicated in Table 4. The samples obtained in this way were irradiated with the LED at 365 nm with a power of 315 mW/cm ² for 1 minute. For decolorization, the samples were irradiated with an LED at 525 nm at 1 W/cm ² for 2 min (PMMA) or 9 min (PC).

The initial coloring and the coloring after irradiation were not identical for PMMA and PC ( 5 ). In addition, the photochemical relaxation time for PMMA was almost five times longer than that for PC, and the thermal relaxation time increased from about 10 hours for PMMA to several days for PC (data not shown). This difference can also be attributed to the different polarity of the thermoplastics, but also to the molecular mobility, which depends on the free volume of the thermoplastic matrix.

PC comprising 0.03 and 0.04 wt.% SP0 was compounded as indicated in Table 4. The samples obtained in this way were irradiated with the LED at 365 nm with a power of 315 mW/cm ² for 1 minute. For decolorization, the samples were irradiated with an LED at 525 nm at 1 W/cm ² for 3 min. (0.03 wt.% SP0) or 9 min. (0.04 wt.% SP0) ( 6 ).

An increase in the amount of SP0 in PC by 33% resulted in a significantly stronger color after one minute of irradiation with the LED at 365 nm.

Example 4 - Cyclic photoactivity of 1,3,3-trimethylindolino-6'-nitrobenzopyrylospiran (SP0)

In a first round of experiments, PC comprising 0.02 and 0.12 wt.% SP0 was compounded and molded as indicated in Table 4 with a cylinder residence time of 10 min at 230 ° C. Samples measuring approximately 20.0 x 10.0 mm and 1.0 mm thick were obtained. The samples obtained in this way were irradiated with the LED at 365 nm with a power of 315 mW/cm ² . For decolorization, the samples were irradiated with an LED at 525 nm at 1 W/cm ² .

The longer the irradiation with the LED at 365 nm with a power of 315 mW/cm ² lasted, the stronger the coloring was and a plateau was quickly reached ( 7 ). When observing the absorption at 595.6 nm, it was found that the sample containing 0.02 wt.% SP0 required 2 minutes to reach the absorption maximum, whereas the sample containing 0.12 wt.% SP0 required 3 minutes minutes. However, the absorption depending on the irradiation time does not show a plateau, but rather a decrease in absorption after reaching the peak value ( 8th ). The effect of concentration on the maximum absorption value is clearly visible, as the absorption increases three times with a 6-fold increase in concentration

After monitoring the absorption at 595.6 nm depending on the irradiation time with the LED at 365 nm, the absorption at 595.6 nm is monitored during irradiation with the LED at 525 with a power of 1 W/cm ² ( 9a) . Once complete photodecolorization is achieved, samples are irradiated with the LED at 365 nm for 10 minutes to monitor thermal decolorization in the dark at room temperature ( 9b) .

According to 9a and 9b Time scales for the two decolorization pathways (photochemical and thermal) are not similar. While the photochemical route requires a few minutes (T _1/2 = 5 sec), the thermal route requires several days (T _1/2 = 105 and 95 min) without reaching the initial coloration before irradiation which is represented by the dashed asymptotes. The decolorization kinetics can therefore be significantly accelerated by using the LED at 525 nm.

• • Proben, die 0,02 Gew.-% SP0 enthalten: 2 Minuten mit LED bei 365 nm (315 mW/cm²), dann 10 Minuten mit LED bei 525 nm (1 W/cm²),
• • Proben, die 0,12 Gew.-% SP0 enthalten: 2:30 Minuten mit LED bei 365 nm (315 mW/cm²) dann 10 Minuten mit LED bei 525 nm (1 W/cm²)

In a second series of tests, PC was compounded comprising 0.02 and 0.12% by weight of SP0 and shaped as indicated in Table 4 with a cylinder residence time of 5 minutes at 230 ° C. The samples obtained in this way were irradiated as follows:

• • Samples containing 0.02 wt% SP0: 2 minutes with LED at 365 nm (315 mW/cm ² ), then 10 minutes with LED at 525 nm (1 W/cm ² ),
• • Samples containing 0.12 wt.% SP0: 2:30 minutes with LED at 365 nm (315 mW/cm ² ) then 10 minutes with LED at 525 nm (1 W/cm ² )

At the end of each irradiation, the absorbance at 595.6 nm was measured by UV-Vis spectroscopy ( 10a) . The maximum absorbance value then gradually decreased over the cycles and at the same time a slight yellow coloration appeared in the sample. The faint yellowish color was also visible upon visual inspection ( 10b) .

Example 5 - Introduction of 1,3,3-trimethylindolino-6'-nitrobenzopyrylospirane (SP0) into PC on a semi-industrial scale

Compounding

PC pellets were produced on the HAAKETM Rheomex CTW100 QC semi-industrial extrusion device, with the direction of rotation of the screws reversed compared to the laboratory version described above. The extrusion temperature was set at 200 °C. Screw speeds of 50 rpm were used. and 100 rpm. used. Amounts ranging from 1 to 15 kg were produced.

A main batch of PC pellets comprising 0.60 wt% SPC was prepared. In a second compounding step, these masterbatch pellets were used to produce PC pellets comprising 0.04% by weight of SP0.

After the second compounding, the color of the final pellets ranged from very light blue and green to very light pink.

Injection molding

The injection molding and extrusion on a semi-industrial scale was carried out as described above using the Krauss-Maffei 160T injection molding machine, which is equipped with a single screw that requires additional heating.

The temperature gradient was as described in Materials and Methods and as in 1 specified, applied inside the cylinder to obtain a sufficiently viscous and homogeneous mixture, trying to maintain the properties of the SP0. The softened material was injected at a temperature of 80 °C into a 167 cm x 84.50 cm x 2.50 mm large, highly polished mold. This temperature was therefore reduced by 60 °C compared to the temperature used in the laboratory.

The plates obtained were made from essentially colorless granules and had a homogeneous, very slightly yellowish appearance.

Properties of the resulting thermoplastic parts

Photoreactivity

Despite the slight initial yellow coloration of the samples, the reactivity of SP0 was maintained. After just 5 seconds of irradiation with the LED at 365 nm with an output of 315 mW/cm ² , a blue color could be observed ( 11a) . The quick color change took place over the entire material thickness of 2.50 mm ( 11b) . Very good resolution was observed during laser writing (laser at 409 nm, 410 mW/cm ² ). It was possible to see the laser dot with the naked eye ( 11c ).

By using a mask, it was possible to create different patterns without causing a spotting effect like the laser. For example, using an LED projector at 395 nm with a power of 100 mW/cm ² , it was possible to obtain a Faurecia font on a 2.50 mm thick PC board containing 0.04 wt.% SP0 in 10 seconds ( 12 ). By incorporating SP0 into the thermoplastic, smart materials can be activated easily and quickly.

It was also possible to use the PC panels initially activated with the LED projector at 395 nm ( 13a and 13b) using an LED at 525 nm and a mask ( 13c , upper part) or a laser at 532 nm ( 13c , lower part) to quickly discolor. A few seconds were enough for a pattern to appear or for the coloring to be completely erased.

Accelerated aging

Since the sprayed plates had good photoreactivity, their stability was examined over a longer period of time. For this purpose, a PC plate without SP0 and a PC plate containing 0.04 wt% SP0 were cut into accelerated aging test specimens. Two test specimens comprising no SP0 and three test specimens comprising 0.04 wt.% SP0 were exposed for 500 hours in the dark at room temperature stored, and two additional sets of three and two samples were stored in an oven at 100 °C for 500 hours.

These samples were then analyzed using UV-Vis spectroscopy to determine the yellowing evolution of the samples based on the L*a*b* data extracted from the absorption spectra. The characteristic quantity for highlighting yellowing is the Δb*. This quantity is the difference between the value of b* at the end of the aging process and the value before. The b* stands for the color from blue to yellow. If the Δb* is positive, yellowing is observed. Since the four Δb* values are less than 2 in absolute numbers, the change in hue is not considered significant (Table 6). Table 6 temperature 500 hours, room temperature 500 hours, 100 °C sample PC PC + 0.04 wt.% SP0 PC PC + 0.04 wt.% SP0 Δb* 0.00 -0.44 0.11 -0.01

These analyzes therefore show that no yellowing occurred over time in these two sets of samples. Large-scale injection molding of the SP0 system into the PC did not alter the stability characteristics of the system over time.

Origin of initial yellowing - influence of high processing temperature

PC pellets containing SP0 prepared with the semi-industrial device were injected into the laboratory device with a barrel temperature of 230 and 300 °C. The samples obtained at 230 °C ( 14a) had a slight pink sheen, similar to the samples obtained from laboratory compounding. However, the samples obtained at 300 °C show a significant deterioration compared to the first sample ( 14b) . The faint yellowish color that appeared in the cylinder after 4 minutes at 300 °C was not observed even after 30 minutes in the cylinder at 230 °C.

This shows that injection at very high temperatures is responsible for the yellowish coloration that occurs when PC plates are injected with SP0.

Example 6 - Organic compounds of type P

Used diarylethenes

1,2-bis(2-Methylbenzo[b]thiophen-3-yl)perfluorcyclopenten DAE1

1,2-bis(2-methylbenzo[b]thiophen-3-yl)perfluorcyclopenten DAE2

,2-bis(5-methyl-2-phenylthiazol-4-yl)perfluorcyclopenten DAE3

1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)perfluorcyclopenten DAE4

1,2-bis(3,5-dimethyl-2-thienyl)perfluorcyclopenten DAE5

1,2-bis(2-ethylbenzo[b ]thiophen-3-yl)perfluorcylopenten DAE6

To investigate the reversible systems, 7 commercially available diarylethenes with the names DAE0 to DAE6 were selected (Table 7). The selected molecules then have the general structure of two heterocycles containing at least one sulfur and two carbon-carbon double bonds. Table 7: Investigated photochromic organic compounds of type P. Surname abbreviation Structural formula cis-1,2-Dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethene DAE0

1,2-bis(2-methylbenzo[b]thiophen-3-yl)perfluorocyclopentene DAE1

1,2-bis(2-methylbenzo[b]thiophen-3-yl)perfluorocyclopentene DAE2

,2-bis(5-methyl-2-phenylthiazol-4-yl)perfluorocyclopentene DAE3

1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)perfluorocyclopentene DAE4

1,2-bis(3,5-dimethyl-2-thienyl)perfluorocyclopentene DAE5

1,2-bis(2-ethylbenzo[b]thiophen-3-yl)perfluorocylopentene DAE6

Thermal stability

The thermal stability of the selected additives was evaluated using thermogravimetric analysis. Stability up to 250 °C, or at least 210 °C for PMMA and at least 190 °C for PC, is desirable in order to integrate the additives into thermoplastics, such as. B. PMMA and PC to enable. Table 8 summarizes temperatures at which a weight loss of 10% by weight occurs and the decomposition temperatures of the compounds used. Table 8: Characteristic decomposition temperatures of photochromic compounds of type T. links Temperature at which 10% weight loss occurs (°C) Decomposition temperature (°C) DAE0 267 325 DAE1 249 308 DAE2 253 320 DAE3 286 346 DAE4 280 341 DAE5 206 272 DAE6 273 343

Compounding

The photochromic compounds were mixed with PMMA and PC at 190°C and 210°C, respectively, in amounts ranging from 0.1 to 0.4% by weight based on the total amount of the composition and as indicated in 15 , mixed using the HAAKETM MiniLab Micro Compounder as described in Materials and Methods. These temperatures produced a slightly viscous and homogeneous thermoplastic at the exit of the extruder while limiting the decomposition of the T-type photochromic compounds. The screw speed was set to 50 rpm. set.

The P-type photochromic molecules were very well miscible with PMMA and PC. Furthermore, the extrudates containing diarylethenes were completely transparent at the extruder exit and no thermochromic phenomenon was observed.

Photoreactivity

After compounding, the photoreactivity of the resulting thermoplastic was tested by irradiation with LED at 365 nm at 315 mW/cm ² for 1 minute ( 15 ).

With the diarylethene used, a wide range of colors could be achieved after irradiation with the LED at 365 nm. Colors ranged from blue to red to pink and even yellow. At a concentration of only 0.1 to 0.4 wt%, a clear color change is observed for all diarylethenes, with the exception of DAE6 in PC, which remained colorless at the chosen irradiation time and dose. In particular, DAE3 and DAE5 showed a very dark color after only one minute of irradiation with LED at 365 nm at a concentration of 0.1 wt%.

Color stability over time

PMMA and PC extrudates containing diarylethenes in the in 16 The stated amounts were stored in the dark after one minute of irradiation with the LED at 365 nm at 315 mW/cm ² for a period of 1 minute to one year.

With the exception of DAE2 in both thermoplastics and DAE5 in PMMA, all samples showed stable coloration for up to one year. In the case of DAE5 in PMMA, this return to the colorless open form occurred within several days. Furthermore, the non-irradiated part of DAE0 showed a balance between the yellow open form and the red closed form, resulting in an orange coloration of the extrudate.

Example 7 - Diarylethene mixtures for a light-sensitive PC

injection

DAE1, which stains blue, DAE3, which stains violet, and DAE5, which stains yellow, were selected to be included in PC.

To further analyze the optical properties of PC containing these molecules, the compounded granules were injected into a mold used to prepare test samples using a HAAKETM MiniJet PRO and as described in Materials and Methods. The parameters are further summarized in Table 9 below. Before injection, the granules were dried in an oven at 100 °C for 4 hours. The cylinder temperature was increased to 280 °C to obtain samples with optical quality, that is, with a transmittance of more than 70% in the visible range (400-800 nm). Table 9: Experimental parameters chosen for forming PC samples with diarylethenes. extrusion dry injection Temperature (°C) Screw speed (rpm) Time (hours) Temperature (°C) Injection pressure (bar) Holding pressure (bar) Cylinder temperature (°C) Mold temperature (°C) 210 50 4 100 800 400 280 120

Previous tests on PC extrudates have shown that for DAE1, DAE3 and DAE5 a concentration of only 0.1% by weight results in a very deep coloration upon irradiation. Therefore, three samples containing 0.1 and 0.5 wt% of each of the three diarylethenes were prepared to study the evolution of haze of the samples upon irradiation depending on the concentration of the photochromic compound. Additionally, PC samples containing mixtures of DAE1 and DAE3 at 0.2 wt% (0.1 wt% DAE1 and 0.1 wt% DAE1) and 0.5 wt% (0. 25 wt% DAE1 and 0.25 wt% DAE3) were formed to investigate possible synergistic effects on light transmittance when photochromic molecules are mixed. Reference samples were prepared by injecting unmodified commercial PC granules under the same conditions ( 17 ). The samples were produced with residence times of 5, 10 and 15 minutes in the barrel of the injection molding machine at 280 °C.

The addition of diarylethene does not significantly change the viscosity of the thermoplastic during the injection process at the concentrations considered. Flowing of the thermoplastic at high temperature occurred in the same manner with and without diarylethenes, and the samples obtained were all the same size. A change in viscosity could cause problems when processing on an industrial scale. In addition, all samples were transparent with no initial color before irradiation. According to the transmission spectra obtained with the UV-Vis spectrophotometer, all samples obtained were of optical quality with a transmittance of more than 70% in the range of 400-800 nm. No significant absorption bands were detected, except for a small amount of absorption in the DAE5-containing samples that absorb between 380 and 410 nm ( 18 ).

To confirm this observation, the specimens were analyzed colorimetrically using the UV-Vis spectrophotometer to obtain the quantities L* (the brightness from black to white), a* (the color from green to red) and b* (the color from blue to yellow). From this data, ΔL*, Δa* and Δb* (difference in quantity value between the sample and the control) could be determined and ΔE could be calculated.

To determine whether the visual appearance of the thermoplastic changed during the injection process, the coloration of the second sample obtained after 10 minutes was compared to that of the first sample obtained after 5 minutes (Table 10). A ΔE less than or equal to 2.0 generally means that no significant color changes occurred. Only the sample containing 0.1 wt% DAE5 resulted in a ΔE greater than 2.0. Table 10: Color changes of the samples after 5 minutes compared to samples after 10 minutes of residence in the cylinder Diarylethylene ΔL* Δa* Δb* ΔE - 0.9 -0.1 -0.1 0.9 0.1% by weight of DAE1 -0.3 0.0 0.3 0.4 0.5% by weight of DAE1 1.2 -0.1 0.2 1.2 0.1% by weight of DAE3 -0.2 0.1 0.2 0.3 0.5% by weight of DAE3 -0.3 -0.1 0.2 0.4 0.1% by weight of DAE5 2.4 0.1 0.3 2.4 0.5% by weight of DAE5 0.0 0.1 -0.1 0.1 0.1% by weight DAE1 + 0.1% by weight DAE3 0.3 0.0 0.2 0.3 0.25% by weight DAE1 + 0.25% by weight DAE3 0.5 0.0 0.4 0.4

The values of Δa* and Δb* were close to zero. So it was mainly a change in clarity with ΔL* equal to 2.4 and not a change in color. This phenomenon could also be observed in the PC reference samples with a ΔL* of 0.9. In general, no yellowing occurred in all samples during the injection period as the Δb* values were all close to zero. Thus, the injection process did not induce coloration due to decomposition, and no noticeable decrease in optical properties was observed even after 10 minutes in the cylinder at 280 °C.

To determine the effects of adding diarylethenes to PC on the initial color of the samples, the coloration of samples obtained after 5 minutes in the cylinder containing diarylethenes was compared to a commercial PC reference sample also obtained after 5 minutes was obtained in the cylinder. For this purpose, the values of ΔL*, Δa*, Δb* and ΔE were determined for each sample (Table 11).

Only the samples containing DAE5 had a ΔE greater than 2.0. However, only the sample containing 0.5% by weight of DAE5 showed a slightly increased positive Δb*. The values of b* going from blue to yellow correspond to an increase towards yellow. In fact, the PC samples with 0.5 wt% DAE5 show a slight absorption around 400-435 nm, which is characteristic of yellow. The sample containing 0.1% by weight of DAE5 has a Δb* value of 1.3, which is still completely acceptable. The ΔL* value of -2.7 results in a ΔE greater than 2.0. Table 11: Influence of the photochromes on the initial color of the samples Diarylethylene ΔL* Δa* Δb* ΔE 0.1% by weight of DAE1 0.5 0.0 0.3 0.6 0.5% by weight of DAE1 -1.2 -0.1 0.7 1.4 0.1% by weight of DAE3 0.4 0.0 0.4 0.6 0.5% by weight of DAE3 0.4 -0.1 0.7 0.8 0.1% by weight of DAE5 -2.7 -0.4 1.3 3.1 0.5% by weight of DAE5 -0.8 -1.6 3.8 4.3 0.1% by weight DAE1 + 0.1% by weight DAE3 0.1 -0.1 0.4 0.4 0.25% by weight DAE1 + 0.25% by weight DAE3 0.3 -0.1 0.6 0.7

None of the three compounds showed signs of degradation during the injection process as no yellowing was observed as the residence time in the cylinder was increased. DAE1 and DAE3 did not cause initial staining of the PC. DAE5 showed a slight yellow color at concentrations above 0.1 wt%.

Colorimetric analysis

The injected sample was irradiated with the LED at 365 nm at a power of 315 mW/cm ² from each mixture after a residence time of 10 minutes in the cylinder at 280 °C. The coloration depending on the irradiation time was then monitored by UV-Vis spectrophotometry.

In each of the samples, visible coloration appeared after only 1 second of irradiation with the LED at 365 nm ( 19 ). Afterwards, with longer irradiation times, a strong coloration to the point of opacity was observed, especially in the samples that each contained 0.5% by weight of DAE1 or DAE3, as well as in the samples that contained a mixture of DAE1 and DAE3 in equal amounts . For each of the samples, coloration was present throughout the thickness of the sample in the irradiated zone.

The absorption spectra of each sample were recorded during irradiation. For each sample, an absorption band appeared from the first second of irradiation. The wavelength at which the absorption is greatest, λ _max , was characteristic of each diarylethene or mixture: 590 nm for DAE1, 534 nm for DAE3, 434 nm for DAE5, and 570 nm for the mixtures of DAE1 and DAE3 (Table 12) . The absorption at wavelengths λ _max was observed depending on the irradiation time ( 20 ). Table 12: Maximum absorption values and associated wavelength and irradiation time. Diarylethylene λ _max (nm) λ _max (au) T _max (sec.) 0.1% by weight of DAE1 590 0.9 420 0.5% by weight of DAE1 590 4.0 5400 0.1% by weight of DAE3 534 0.4 420 0.5% by weight of DAE3 534 3.2 2100 0.1% by weight of DAE5 434 0.5 360 0.5% by weight of DAE5 434 1.2 900 0.1% by weight DAE1 + 0.1% by weight DAE3 570 1.5 1500 0.25% by weight DAE1 + 0.25% by weight DAE3 570 3.4 2400

The transmission spectra show the degree of transmittance depending on the irradiation time ( 21 ). After just one second of irradiation, the transmittance at the characteristic wavelength of each diarylethene composition decreased sharply. For the most concentrated samples containing DAE1 and/or DAE3, the transmittance even reached 0% when the irradiation was prolonged, as indicated in 21 , over a wide wavelength range. This is well below the desired 7%, which characterizes the opacity of the sample according to industrial specifications. Samples containing 0.5 wt% DAE5 and the mixture of DAE1 and DAE3 with 0.2 wt% also achieved transmittance below 7% for several wavelength values in the visible range (Table 13). Table 13: Wavelength range in which the transmittance is less than 7%, depending on the composition of the PC samples containing diarylethenes. 0.5% by weight of DAE1 0.5% by weight of DAE3 0.5% by weight of DAE5 0.1% by weight DAE1 + 0.1% by weight DAE3 0.25% by weight DAE1 + 0.25% by weight DAE3 488-670 nm 450-608 nm 300-447 nm 518-612 nm 469-635 nm

Depending on the criteria set by the user, it is thus possible to obtain PC samples that are opaque at wavelengths between 300 and 670 nm ( 22 ).

The development of the color of the samples under irradiation can be analyzed by a colorimetric examination. It is then possible to represent each color obtained for each sample at a specific irradiation time in the L*a*b* frame ( 23 ).

It is noteworthy that the value of luminosity L* (0 = black, 100 = white), which was initially close to 90 for all samples, changed significantly during irradiation, except for the DAE5-containing Pro ben, where it remained constant ( 24 ). For the samples containing DAE1 and/or DAE3, this value decreased significantly with increasing irradiation time until it reached values between 23 and 10 for the PC samples with the highest concentrations of DAE1 and/or DAE3. With these formulations, very dark samples can be obtained which, after irradiation, are very close to the desired black or complete opacity, in particular the sample containing the mixture of 0.25% by weight of DAE1 and 0.25% by weight of DAE3.

The results show that it was possible to obtain photochromic PC samples capable of coloring in a few seconds and even becoming opaque over a range of wavelengths, for samples containing 0.5 wt. -% DAE1 or DAE3, as well as for the samples containing the mixture of 0.25% by weight DAE1 and 0.25% by weight DAE3.

Aging behavior

After examining the coloration of the compounds in the PC, accelerated aging was performed at 100 °C for 500 hours to determine the shelf life of the colored (closed) and colorless (open) forms of each sample. For this purpose, after a residence time of 5 minutes in the cylinder at 280 ° C of each mixture, the injected samples were irradiated with the LED at 365 nm at a power of 315 mW / cm ² according to the times defined in Table 14 and determined above ( 20 ) to achieve a stabilized maximum coloration. Table 14: Irradiation time with the LED at 365 nm depending on the composition of the sample. Diarylethylene Irradiation time (min.) 0.1% by weight of DAE1 25 0.5% by weight of DAE1 180 0.1% by weight of DAE3 6 0.5% by weight of DAE3 50 0.1% by weight of DAE5 7 0.5% by weight of DAE5 16 0.1% by weight DAE1 + 0.1% by weight DAE3 20 0.25% by weight DAE1 + 0.25% by weight DAE3 75

After irradiation, the test specimens were stored in an oven at 100 °C in the dark. After 500 hours, a slight loss of color was observed in the samples containing 0.1% by weight of DAE1, 0.5% by weight of DAE3 and the mixture of 0.1% by weight of DEA1 and 0.1% by weight of DAE3 . The coloration of the other 5 samples containing diarylethenes appears to be unchanged and no yellowing is observed in the non-irradiated zone for all samples ( 25 ).

To further characterize these observations, the Δb* of the non-irradiated portion of each sample was monitored during the aging period ( 26 ), and the values of Δb* between t = 500 hours and t = 0 are given in Table 15. Table 15: Development of the Δb* of the non-irradiated area after 500 hours at 100 °C depending on the composition of the PC sample. Diarylethylene Δb* - -0.6 0.1% by weight of DAE1 -0.7 0.5% by weight of DAE1 -9.5 0.1% by weight of DAE3 -0.6 0.5% by weight of DAE3 -0.9 0.1% by weight of DAE5 0.2 0.5% by weight of DAE5 0.6 0.1% by weight DAE1 + 0.1% by weight DAE3 -0.9 0.25% by weight DAE1 + 0.25% by weight DAE3 -2.6

This quantity made it possible to detect the presence of yellowing, which could be due to decomposition of PC or photochromic compounds without irradiation. The absolute Δb* values were between 0 and 2.0 after 500 hours, except for the PC sample containing 0.5 wt% DAE1 and the sample containing the mixture of 0.25 wt% DAE1 and 0.25% by weight of DAE3. The value of Δb* in this case was less than 0, which corresponds to an increase in the blue hue.

This can be explained by the slight blue color in the non-irradiated area, which occurs due to diffusion during irradiation in the lower area of the sample. The measurement at the initial time was carried out before the irradiation, when the blue color was not yet present in this non-irradiated area. However, the values of Δb* did not fluctuate by more than 2 units over time ( 23 ), which suggests that the material in the non-irradiated part did not yellow during accelerated aging.

In addition, the development of the color of the samples in the irradiated area can be characterized by the ΔE. The samples containing only DAE3 and DAE5 and the sample containing 0.5 wt% DEA1 showed relatively stable coloration over the 500 hours, even though the ΔE values were close to 2.0. In the samples containing 0.1% DAE1 and the sample containing a mixture of 0.1% by weight DAE1 and 0.1% by weight DEA3, a continuous development of the color with increasing ΔE slightly above 2.0 was observed ( 27 ).

Generally, a color change was observed in the irradiated areas (Table 16). However, the samples containing DAE3, DAE5 and the sample comprising a mixture of 0.25 wt% DAE1 and 0.25 wt% DAE3 had a ΔE of slightly over 2.0 and were acceptable. When ΔE is greater than 2.0, the human eye can distinguish the two colors, but depending on the application, a larger difference can be accepted. Table 16: Development of the color of the irradiated area after 500 hours at 100 °C depending on the composition of the PC sample. Diarylethylene ΔL* Δa* Δb* ΔE 0.1% by weight of DAE1 4.0 -2.3 6.6 8.0 0.5% by weight of DAE1 2.5 -3.5 0.2 4.3 0.1% by weight of DAE3 -1.9 2.6 -0.7 3.3 0.5% by weight of DAE3 0.9 0.4 2.2 2.4 0.1% by weight of DAE5 0.0 -0.1 -1.4 1.4 0.5% by weight of DAE5 0.3 -0.6 -2.6 2.7 0.1% by weight DAE1 + 0.1% by weight DAE3 3.8 -2.0 5.0 6.6 0.25% by weight DAE1 + 0.25% by weight DAE3 2.1 -1.5 1.8 3.2

Samples used for a staining study were stored at room temperature and in the dark for two months to determine whether the decolorization observed in certain samples was due to initial relaxation. Table 17: Development of color after 2 months at room temperature depending on the composition of the PC sample. Diarylethylene ΔL* Δa* Δb* ΔE 0.1% by weight of DAE1 -0.5 0.5 -0.7 1.0 0.5% by weight of DAE1 -0.2 0.0 0.2 0.3 0.1% by weight of DAE3 0.4 -0.3 0.5 0.7 0.5% by weight of DAE3 0.5 0.3 0.7 0.9 0.1% by weight of DAE5 0.0 0.4 -3.4 3.5 0.5% by weight of DAE5 -0.2 -0.3 -0.3 0.5 0.1% by weight DAE1 + 0.1% by weight DAE3 -1.7 1.0 0.1 2.0 0.25% by weight DAE1 + 0.25% by weight DAE3 -0.2 -0.3 0.5 0.6

The ΔE values remained below 2.0 for the majority of samples (Table 17), so there was no relaxation in the early stages. However, a loss of yellow coloration was observed in the sample containing 0.1% by weight of DAE5 with a Δb* of -3.4. In particular, the samples containing 0.5 wt% DAE1, DAE5 and the mixture of 0.5 wt% DAE1 and DAE3 had stability of their coloring with a ΔE value of less than 0.6.

Example 8 - Introduction of diarylethenes into PC on a semi-industrial scale

Compounding

Compounding of diarylethenes with PC granules was carried out on the HAAKETM Rheomex CTW100 QC semi-industrial compounder as described in Materials and Methods, producing an extrudate at a rate of 1 kg/hr. was obtained. The temperature in the cylinder of the semi-industrial device was set at 190 °C. Samples were prepared comprising a final amount of 0.25 wt% DAE1 and 0.25 wt% DAE3 formulation in PC.

The sample, comprising a mixture of 0.25 wt% DAE1 and 0.25 wt% DAE3, was obtained from a masterbatch comprising 2.5 wt% for each of the two diarylethenes.

The rotation speed of the screws was set to 25 rpm for the masterbatch. and for dilution to the desired final mixture at 100 rpm. set.

The resulting masterbatch pellets had a slight bluish color (not shown), which disappeared after dilution with pure commercial PC pellets to the final concentration. No thermochromic phenomena were observed for this family of molecules. The granules containing the two diarylethenes in a concentration of 0.25% by weight ( 28c ), therefore looked visually identical to the commercially available PC granulate ( 28a) and the PC granules that were extruded without diarylethenes ( 28b) .

DSC analyzes were performed on pellets obtained in the semi-industrial compounder and compared with pellets produced on a laboratory scale. The characteristic signal of the glass transition temperature around 144 °C was not affected by the mixing procedures (data not shown).

injection

Plates measuring 167.00 x 84.50 mm and 2.50 mm thick were fabricated using unmodified commercial PC granules, the commercial PC granules once cast on the HAAKETM Rheomex semi-industrial apparatus described in Materials and Methods CTW100 QC Compounder (same parameters for each batch) and produced using the PC granules compounded with 0.25 wt% DAE1 and 0.25 wt% DAE3 on the semi-industrial equipment.

Before injection, the unmodified commercial PC granules, the commercial PC granules extruded once on the semi-industrial compounder, and the PC granules containing 0.25 wt% DAE1 and 0.25 wt% DAE3 compounded on the semi-industrial compounder, stored in drying ovens at 120 °C for 5, 7 and 8 hours, respectively, which is an optional step.

The rotation speed of the injection screw was set to 100 rpm. set. A temperature gradient was applied to the screw barrel ( 1 ). The inlet temperature is determined so that the material is sufficiently liquid to be delivered to the injection head.

The temperature was gradually increased towards the outlet ( 1 ) to reach a high enough temperature to exceed the cold point corresponding to the non-temperature controlled nozzle. The mold temperature was set at 90 °C and the cycle time was 30 seconds. The parameters were used for the three pellet batches examined (commercial, commercially extruded and compounded with 0.25 wt.% DAE1 and 0.25 wt.% DAE3).

The plates obtained from the three batches showed good transparency ( 29a-c ). Plates containing diarylethenes did not show any pronounced coloration ( 29c ). Despite the high extrusion temperatures of up to 320 °C, the panels showed no defects or spotting.

The measurements of L*, a* and b* on the three batches of sprayed panels allowed the individual ΔE to be determined. The ΔE between panels made from once-extruded pellets and panels made from commercial pellets was 0.9. The ΔE between panels made from once-extruded pellets and panels made from compounded pellets comprising 0.25 wt% DAE1 and 0.25 wt% DAE3 was 0.8. The ΔE between sheets made from compounded pellets comprising 0.25 wt% DAE1 and 0.25 wt% DAE3 and sheets made from once-extruded pellets was 0.3.

It was shown that no decomposition of PC or photochromic compounds occurs when injected at very high temperatures. This is surprising since, according to the thermogravimetric analysis, 91% of DAE1 and 37% of DAE3 should have decomposed at 320 °C.

Properties of the resulting thermoplastic parts

Photoreactivity

A mask was placed on half of a 2.5 mm thick PC board comprising 0.25 wt% DAE1 and 0.25 wt% DAE3, the other half was exposed to an LED projector at 395 for 2 minutes nm exposed to 100 mW/cm ² . The coloring achieved was very homogeneous and appeared only in the area exposed to irradiation ( 30a) .

The same plate was then exposed only in the center under an LED at 525 nm for 1 minute at 1 W/cm ² . The color then disappeared only in the irradiated area, without changing the colorless form of the diarylethenes ( 30a) . Laser writing could also be carried out on the sprayed panels with good spatial resolution, with the color change again occurring in the thickness of the material ( 30b) .

In a second step, the coloration was examined in more detail and compared with the results previously obtained with the laboratory-scale samples with a thickness of only 1.0 mm. From the 2.5 mm thick sprayed panels, PC test specimens comprising 0.25 wt.% DAE1 and 0.25 wt.% DAE3 of 10 x 60 mm were produced and with PC test specimens comprising 0.25 wt.% DAE1 and 0.25% by weight DAE3 of 10 x 60 mm and a thickness of 1 mm were compared. The color of the samples was monitored depending on the irradiation time with the LED at 365 nm at 315 mW/cm ² ( 31 ).

Coloring was achieved at both strengths after just 1 second of irradiation. For the 2.5 mm sample, an irradiation time of at least 180 seconds was required to achieve homogeneous coloring across the entire thickness and opaque coloring.

The absorbance of the PC samples comprising 0.25 wt% DAE1 and 0.25 wt% DAE3 in both strengths was further monitored using the UV-Vis spectrophotometer. The absorption maximum wavelength, 570 nm, remained unchanged with strength, and the absorption at this wavelength also increased. Although the absorption was slightly lower for the 2.5 mm sample, it leveled off after 50 minutes of irradiation and then became more noticeable ( 32 ). The maximum time required to achieve constant absorption was therefore greater: 4500 seconds for a thickness of 2.5 mm compared to 2400 seconds for 1.0 mm.

Using the transmission spectra, the values of L*, a* and b* could be monitored depending on the irradiation time for the two different strengths ( 33 ). The color development was approximately the same for both strengths.

The hue h° was identical for both sample thicknesses (data not shown), but the saturation C* became higher for the 2.5 mm sample after 10 minutes of irradiation. Like the transmittance, the luminosity L* also decreased slightly less quickly in the 2.5 mm sample, but reached the same minimum after 4500 seconds of irradiation ( 34 ). The color achieved does not depend on the thickness of the sample.

Accelerated aging

Samples from each batch of injected 2.5 mm thick PC sheets (made from commercial pellets, made from commercial pellets once extruded, made from pellets containing 0.25 wt% DAE1 and 0.25 wt% DAE3 compounded) were aged in the oven for 500 hours in the dark at 100 °C. In addition, a sprayed PC plate made from pellets containing the diarylethene mixture of 0.25 wt% DAE1 and 0.25 wt% DAE was exposed to the LED at 365 nm at 315 for 35 minutes mW/cm ² and then aged in an oven in the dark at 100 °C for 500 hours.

After aging, no yellowing is observed in all samples and the blue color does not appear to be affected. The coloring of the originally irradiated sample remains deep, homogeneous and localized across the irradiated area ( 35 ).

To confirm these observations, the color change of the samples during aging was monitored using UV-Vis spectrophotometry. The quantities ΔL*, Δa*, Δb* and ΔE were calculated from the data obtained during transmission (Table 18). Only the ΔE value for the stained PC samples was higher than 2.0, but remained very close to this value. especially for the samples without color change, all absolute Δb* values were not higher than 2.0. Thus, no yellowing due to the extrusion process or the presence of diarylethenes was determined. Table 18: Color development after 500 hours at 100 °C depending on the composition of 2.5 mm thick PC boards ΔL* Δa* Δb* ΔE Injected 0.2 0.0 0.0 0.2 Extruded 0.3 0.0 -0.3 0.5 Compounded with 0.25 wt.% DAE1 and 0.25 wt.% DAE3 0.3 0.0 0.0 0.3 Compounded with 0.25 wt.% DAE1 and 0.25 wt.% DAE3 and irradiated 3.6 -2.6 2.4 5.0

The mixture of 0.25 wt% DAE1 and 0.25 wt% DAE3 in PC therefore showed very good resistance to compounding and injection processes, and the stability of the colored mold over time was excellent.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

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Claims (29)

A photochromic polymer composition comprising: (a) 90.00 to 99.99% by weight of a polymer selected from the group consisting of polycarbonate (PC) and poly(methyl methacrylate) (PMMA) and mixtures thereof; and (b) 0.01 to 10.00% by weight of at least one photochromic compound selected from the group consisting of: (i) a spiropyran of formula (I)

where R ₁ is selected from C _1-6 alkyl, C _2-6 alkenyl, C _1-6 hydroxyalkyl; R ₂ and R ₃ are independently selected from C _1-6 alkyl and C _2-6 alkenyl, or wherein R ₂ and R ₃ together form C ₃ -C ₇ cycloalkyl; R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , C _1-6 alkyl, C _2-6 alkenyl and C _1-6 alkoxy, where at least one of R ₄ , R ₅ and R ₆ -NO ₂ is. and/or (ii) a diarylethene of the formula (IIa), (IIb) or (IIc)

where R ₇ and R ₇ are both -CN, or R ₇ and R _7' together form a perfluorinated cyclopentene ring; R ₈ and R _8' are identical and are selected from H, C _1-6 alkyl and C _2-6 alkenyl; R ₈ and R _9' are identical and are selected from H, C _1-6 alkyl, C _2-6 alkenyl, phenyl and benzyl; R ₁₀ and R _10' are identical and are selected from H, C _1-6 alkyl, C _2-6 alkenyl, phenyl and benzyl; R ₁₁ and R _11' are identical and are selected from H, C _1-6 alkyl, C _2-6 alkenyl, phenyl and benzyl; or where in formula (Ila) R ₉ /R _9' and R ₁₀ /R _10' together form a benzene ring;wherein the quantities refer to the total weight of the photochromic polymer composition. Photochromic polymer composition according to Claim 1 , where R ₁ is selected from methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, ethenyl, propen-1-yl, buten-1 -yl, penten-1-yl, hexen-1-yl, hydroxymethyl, 1-hydroxyethyl, 1-hydroxypropyl, 2-hydroxypropyl, 1-hydroxybutyl, 1-hydroxypentyl, 1-hydroxyhexyl. Photochromic polymer composition according to Claim 2 , where R ₁ is selected from methyl, hexyl and 1-hydroxyethyl. Photochromic polymer composition according to one of the preceding claims, wherein R ₂ and R ₃ are independently selected from methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, ethenyl, propen-1-yl, buten-1- yl, penten-1-yl, hexen-1-yl, or where R ₂ and R ₃ together form cyclopentyl, cyclohexyl or cycloheptyl. Photochromic polymer composition according to Claim 4 , where R ₂ and R ₃ are both methyl or where R ₂ and R ₃ form cyclohexyl. Photochromic polymer composition according to one of the preceding claims, wherein R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl , n-pentyl, n-hexyl, ethenyl, propen-1-yl, buten-1-yl, penten-1-yl, hexen-1-yl, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy , sec-butoxy, tert-butoxy, n-pentoxy, n-hexoxy. Photochromic polymer composition according to Claim 6 , where R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, n- Hexoxy. Photochromic polymer composition according to Claim 6 or 7 , where R ₄ , R ₅ and R ₆ are independently selected from H, -NO ₂ , methyl, sec-butyl and methoxy. Photochromic polymer composition according to any one of the preceding claims, wherein one of R ₄ , R ₅ and R ₆ is -NO ₂ . Photochromic polymer composition according to one of the preceding claims, wherein R ₈ and R _8' are identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl , n-hexyl, ethenyl, propen-1-yl, buten-1-yl, penten-1-yl and hexen-1-yl. Photochromic polymer composition according to Claim 10 , where R ₈ and R _8' are identical and are selected from methyl and ethyl, preferably where R ₈ and R _8' are identical and are methyl. Photochromic polymer composition according to one of the preceding claims, wherein R ₈ and R _9' are identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl , n-hexyl, ethenyl, propen-1-yl, buten-1-yl, penten-1-yl, hexen-1-yl, phenyl and benzyl. Photochromic polymer composition according to Claim 12 , where R ₈ and R _9' are identical and are selected from methyl and phenyl. Photochromic polymer composition according to one of the preceding claims, wherein R ₁₀ and R _10' are identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl , n-hexyl, ethenyl, propen-1-yl, buten-1-yl, penten-1-yl, hexen-1-yl, phenyl and benzyl. Photochromic polymer composition according to Claim 14 , where R ₁₀ and R _10' are identical and are H or methyl. Photochromic polymer composition according to one of the preceding claims, wherein R ₁₁ and R _11' are identical and are selected from H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl , n-hexyl, ethenyl, propen-1-yl, buten-1-yl, penten-1-yl, hexen-1-yl, phenyl and benzyl. Photochromic polymer composition according to Claim 16 , where R ₁₁ and R _11' are identical and are H or methyl. Photochromic polymer composition according to one of the preceding claims, wherein the spiropyran is selected from the group consisting of:

Photochromic polymer composition according to one of the preceding claims, wherein the diarylethene is selected from the group consisting of:

Photochromic polymer composition according to one of the preceding claims, wherein the photochromic compound is in an amount of 0.01 to 5.00% by weight, preferably 0.01 to 2.00% by weight, more preferably 0.01 to 0.09 % by weight, most preferably in the amount of 0.03 to 0.60% by weight, based on the total weight of the photochromic polymer composition. Photochromic polymer composition according to one of the preceding claims, wherein the composition is free of volatile organic compounds (VOC). Article, preferably an injection molded article, comprising the composition according to one of Claims 1 until 21 , wherein the article is preferably in the form of a film, a plate or a panel. Process for producing the photochromic composition according to one of Claims 1 until 21 , the method comprising compounding PC or PMMA and a photochromic compound to form the thermoplastic composition. Procedure according to Claim 23 , wherein the compounding is carried out at a temperature in the range of 180 to 230 ° C. Process for producing the article Claim 22 , the method comprising compounding a PC or PMMA and a photochromic compound to form a thermoplastic composition, followed by injecting and molding the thermoplastic composition into the article. Procedure according to Claim 25 , wherein the compounding is carried out at a temperature in the range of 180 to 230 ° C. Procedure according to Claim 25 or 26 , wherein the injection is carried out at a temperature gradient in the range of 220 to 350 ° C. Procedure according to one of the Claims 25 until 27 , wherein molding is carried out at a temperature in the range of 80 to 120 °C. Procedure according to one of the Claims 23 until 28 , wherein the process is carried out in the absence of volatile organic components (VOC).